Update pydantic requirement from ~=2.5.2 to ~=2.6.3 (#26)

Updates the requirements on [pydantic](https://github.com/pydantic/pydantic) to permit the latest version.
- [Release notes](https://github.com/pydantic/pydantic/releases)
- [Changelog](https://github.com/pydantic/pydantic/blob/main/HISTORY.md)
- [Commits](pydantic/pydantic@v2.5.2...v2.6.3)

---
updated-dependencies:
- dependency-name: pydantic
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

requirements.txt

@@ -1,4 +1,4 @@
 python-telegram-bot~=20.8
 panflute~=2.5.2
 gql[aiohttp]~=3.5.0
-pydantic~=2.5.2
+pydantic~=2.6.3