Bump python-telegram-bot from 21.5 to 21.8

Bumps [python-telegram-bot](https://github.com/python-telegram-bot/python-telegram-bot) from 21.5 to 21.8.
- [Release notes](https://github.com/python-telegram-bot/python-telegram-bot/releases)
- [Changelog](https://github.com/python-telegram-bot/python-telegram-bot/blob/master/CHANGES.rst)
- [Commits](python-telegram-bot/python-telegram-bot@v21.5...v21.8)

---
updated-dependencies:
- dependency-name: python-telegram-bot
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

requirements.txt

@@ -17,7 +17,7 @@ protobuf
 pyasn1==0.6.1
 pyasn1-modules==0.4.1
 python-dotenv==1.0.1
-python-telegram-bot==21.5
+python-telegram-bot==21.8
 requests==2.32.3
 rsa==4.9
 sniffio==1.3.1