Bump python-telegram-bot from 13.12 to 21.6

Bumps [python-telegram-bot](https://github.com/python-telegram-bot/python-telegram-bot) from 13.12 to 21.6.
- [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@v13.12...v21.6)

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

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

requirements.txt

@@ -9,7 +9,7 @@ pdfCropMargins
 pdf2image
 pdfminer.six
 python-dotenv
-python-telegram-bot==13.12
+python-telegram-bot==21.6
 Pillow
 PyPDF2
 requests