[release] Version 1.3.0

[gchan]

Description

This PR bumps the version to 1.3.0 and documents new features that have been merged since the 1.2.0 release.

The 1.3.0 release includes three significant improvements:

1. A new --tag-filters option that enables filtering tests by execution_tag markers with key:value pairs (Add --tag-filters option to filter tests using execution_tag marker #83)
2. Proper reporting of fixture teardown failures, which were previously ignored and left tests incorrectly marked as passed (fix: report teardown failures as failed tests #86, fixes Failures on teardown are ignored and the test is reported as passed #84)
3. A fix for test data upload when pytest-xdist is enabled but numprocesses is set to 0 (Test data not being uploaded for xdist enabled but numprocesses set to 0 #81)

The README now documents the new --tag-filters feature with usage examples, helping users understand how to filter tests based on Test Engine tags.

Context

Relates to TE-5145

Changes

• Update version from 1.2.0 to 1.3.0 in pyproject.toml
• Add "Filtering Tests by Tags" section to README.md with usage examples
• Regenerate uv.lock to reflect new version

Verification

Version correctly updated:

grep "version.*1.3.0" pyproject.toml uv.lock

Documentation renders correctly in markdown preview.

Deployment

Low risk. This is a standard release preparation PR. The actual package release will be triggered by merging this PR, which will invoke the automated release pipeline.

Rollback

Yes

[gchan]

Release notes for the GitHub release:

## What's Changed

### Added
* Add `--tag-filters` option to filter tests using `execution_tag` marker by @nprizal in https://github.com/buildkite/test-collector-python/pull/83

### Fixed
* Report teardown failures as failed tests by @jimsynz in https://github.com/buildkite/test-collector-python/pull/86
  * Teardown failures are now correctly reported instead of being ignored (fixes #84)
  * Fixed `ValueError` when pytest-xdist is not installed
* Test data not being uploaded for xdist enabled but numprocesses set to 0 by @zpoint in https://github.com/buildkite/test-collector-python/pull/81

## New Contributors
* @zpoint made their first contribution in https://github.com/buildkite/test-collector-python/pull/81

**Full Changelog**: https://github.com/buildkite/test-collector-python/compare/v1.2.0...v1.3.0