Update rich requirement from ~=13.7.0 to ~=13.8.0

Updates the requirements on [rich](https://github.com/Textualize/rich) to permit the latest version.
- [Release notes](https://github.com/Textualize/rich/releases)
- [Changelog](https://github.com/Textualize/rich/blob/master/CHANGELOG.md)
- [Commits](Textualize/rich@v13.7.0...v13.8.0)

---
updated-dependencies:
- dependency-name: rich
  dependency-type: direct:development
...

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

requirements.dev.txt

@@ -1,4 +1,4 @@
-rich~=13.7.0
+rich~=13.8.0
 pynacl~=1.5.0
 aiofiles~=23.2.1