Bump importlib-metadata from 5.1.0 to 6.8.0

Bumps [importlib-metadata](https://github.com/python/importlib_metadata) from 5.1.0 to 6.8.0.
- [Release notes](https://github.com/python/importlib_metadata/releases)
- [Changelog](https://github.com/python/importlib_metadata/blob/main/NEWS.rst)
- [Commits](python/importlib_metadata@v5.1.0...v6.8.0)

---
updated-dependencies:
- dependency-name: importlib-metadata
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

requirements.txt

@@ -36,7 +36,7 @@ h11==0.14.0
 httplib2==0.21.0
 icalendar==5.0.3
 idna==3.4
-importlib-metadata==5.1.0
+importlib-metadata==6.8.0
 iniconfig==1.1.1
 lxml==4.9.1
 markdownify==0.11.6