Update colorlog requirement from ~=6.7 to ~=6.8

Updates the requirements on [colorlog](https://github.com/borntyping/python-colorlog) to permit the latest version.
- [Release notes](https://github.com/borntyping/python-colorlog/releases)
- [Commits](borntyping/python-colorlog@v6.7.0...v6.8.0)

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

Signed-off-by: dependabot[bot] <support@github.com>

requirements.txt

@@ -1,4 +1,4 @@
 aiohttp~=3.9
 attrs~=23.1
-colorlog~=6.7
+colorlog~=6.8
 multidict~=6.0