Update version in fdroid repo

[MrRulf]

Firefly III Server Version:
5.7.18

Firefly III Mobile Version:
5.0.3

Android Version:
13

Device Information:

• BRAND: Fairphone
• MODEL: 4

---

Expected Behavior

the repo exists to deliver updates faster so it should have the latest version before fdroid

Current Behavior

the repo does not have the latest version but inly 5.0.3

Steps to Reproduce

add repo to fdroid, look at versions

[MrRulf]

I understand if the repo is not supported anymore, but then it should be removed from the readme