Migrate populate_contributors.py to Python 3 and add automated monthly update workflow

[Copilot]

The populate_contributors.py script uses Python 2's deprecated urllib2 module. This PR migrates it to Python 3 and adds a GitHub Actions workflow to automatically update the contributors table in the apps-android-commons README monthly.

Changes

Python 3 Migration

• Replace urllib2 with urllib.request in populate_contributors.py
• Add User-Agent header to avoid 403 errors from GitHub API

New update_readme.py Script

• Standalone script to surgically replace only the Contributors table in README
• Pattern matches between ## Contributors ## and .. and [many more] markers
• Error handling with validation that target section exists before updating

Automated Workflow

• Runs 1st of each month at 00:00 UTC via cron
• Fetches contributors from GitHub API, generates markdown table, updates apps-android-commons README
• Supports manual triggering via workflow_dispatch
• Requires PAT_TOKEN secret with write access to target repository

on:
  schedule:
    - cron: '0 0 1 * *'
  workflow_dispatch:

Setup Required

Add a repository secret PAT_TOKEN with permissions to push to commons-app/apps-android-commons.

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• https://api.github.com/repos/commons-app/apps-android-commons/contributors
  • Triggering command: python populate_contributors.py (http block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

Original prompt

• update the populate_contributors.py script to use urllib.request instead of urllib2
• create a github workflow that we could run to modify the README directly at https://github.com/commons-app/apps-android-commons.
• add a cron job in the workflow that runs every month and shows the latest list of contributors.
• Here's how the README looks like, ensure the workflow just changes the Contributors table:

# Wikimedia Commons Android app
![GitHub issue custom search](https://img.shields.io/github/issues-search?label=%22good%20first%20issue%22%20issues&query=repo%3Acommons-app%2Fapps-android-commons%20is%3Aissue%20is%3Aopen%20label%3A%22good%20first%20issue%22)
[![Build status](https://github.com/commons-app/apps-android-commons/actions/workflows/android.yml/badge.svg?branch=main)](https://github.com/commons-app/apps-android-commons/actions?query=branch%3Amain)
[![Preview the app](https://img.shields.io/badge/Preview-Appetize.io-orange.svg)](https://appetize.io/app/8ywtpe9f8tb8h6bey11c92vkcw)
[![codecov](https://codecov.io/gh/commons-app/apps-android-commons/branch/master/graph/badge.svg)](https://codecov.io/gh/commons-app/apps-android-commons)

The Wikimedia Commons Android app allows users to upload pictures from their Android phone/tablet to Wikimedia Commons. Download the app [here][1], or view our [website][2].

Initially started by the Wikimedia Foundation, this app is now maintained by grantees and volunteers of the Wikimedia community. Anyone is welcome to improve it, just choose among the [open issues][3] and send us a pull request! :-) 

<a href="https://f-droid.org/repository/browse/?fdid=fr.free.nrw.commons" target="_blank">
<img src="https://upload.wikimedia.org/wikipedia/commons/archive/9/96/20200131184248%21%22Get_it_on_F-droid%22_Badge.png" alt="Get it on F-Droid" height="90"/></a>
<a href="https://play.google.com/store/apps/details?id=fr.free.nrw.commons" target="_blank">
<img src="https://play.google.com/intl/en_us/badges/images/generic/en-play-badge.png" alt="Get it on Google Play" height="90"/></a>

## Documentation

Our [documentation repository][4] contains extensive documentation for users, contributors, and developers alike:

* [User Documentation][5]
* [Contributor Documentation][6]
  * [Volunteers Welcome!][7]
* [Developer Documentation][8]
  * [Libraries Used][9]

## Contributors ##

Thank you all for your work!

| [<img src="https://avatars.githubusercontent.com/u/3611199?v=4" width="100px;"/><br /><sub><b>misaochan</b></sub>](https://github.com/misaochan) | [<img src="https://avatars.githubusercontent.com/u/24829418?v=4" width="100px;"/><br /><sub><b>translatewiki</b></sub>](https://github.com/translatewiki) | [<img src="https://avatars.githubusercontent.com/u/3127881?v=4" width="100px;"/><br /><sub><b>neslihanturan</b></sub>](https://github.com/neslihanturan) | [<img src="https://avatars.githubusercontent.com/u/30430?v=4" width="100px;"/><br /><sub><b>yuvipanda</b></sub>](https://github.com/yuvipanda) | [<img src="https://avatars.githubusercontent.com/u/99590?v=4" width="100px;"/><br /><sub><b>nicolas-raoul</b></sub>](https://github.com/nicolas-raoul) |
| :---: | :---: | :---: | :---: | :---: |
| [<img src="https://avatars.githubusercontent.com/u/407647?v=4" width="100px;"/><br /><sub><b>psh</b></sub>](https://github.com/psh) | [<img src="https://avatars.githubusercontent.com/u/4953590?v=4" width="100px;"/><br /><sub><b>domdomegg</b></sub>](https://github.com/domdomegg) | [<img src="https://avatars.githubusercontent.com/u/3069373?v=4" width="100px;"/><br /><sub><b>maskaravivek</b></sub>](https://github.com/maskaravivek) | [<img src="https://avatars.githubusercontent.com/u/30932899?v=4" width="100px;"/><br /><sub><b>madhurgupta10</b></sub>](https://github.com/madhurgupta10) | [<img src="https://avatars.githubusercontent.com/u/17375274?v=4" width="100px;"/><br /><sub><b>ashishkumar468</b></sub>](https://github.com/ashishkumar468) |
| [<img src="https://avatars.githubusercontent.com/u/103075?v=4" width="100px;"/><br /><sub><b>bvibber</b></sub>](https://github.com/bvibber) | [<img src="https://avatars.githubusercontent.com/u/10674?v=4" width="100px;"/><br /><sub><b>whym</b></sub>](https://github.com/whym) | [<img src="https://avatars.githubusercontent.com/u/10153800?v=4" width="100px;"/><br /><sub><b>akaita</b></sub>](https://github.com/akaita) | [<img src="https://avatars.githubusercontent.com/u/12448084?v=4" width="100px;"/><br /><sub><b>sivaraam</b></sub>](https://github.com/sivaraam) | [<img src="https://avatars.githubusercontent.com/u/6900601?v=4" width="100px;"/><br /><sub><b>veyndan</b></sub>](https://github.com/veyndan) |
| [<img src="https://avatars.githubusercontent.com/u/19607555?v=4" width="100px;"/><br /><sub><b>ujjwalagrawal17</b></sub>](https://github.com/ujjwalagrawal17) | [<img src="https://avatars.githubusercontent.com/u/3358282?v=4" width="100px;"/><br /><sub><b>macgills</b></sub>](https://github.com/macgills) | [<img src="https://avatars.githubusercontent.c...

</details>



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[RitikaPahwa4444]

Going through the script. The header is not really required, need to validate the rest of the changes.