Bump coverage from 7.5.3 to 7.6.4

Bumps [coverage](https://github.com/nedbat/coveragepy) from 7.5.3 to 7.6.4.
- [Release notes](https://github.com/nedbat/coveragepy/releases)
- [Changelog](https://github.com/nedbat/coveragepy/blob/master/CHANGES.rst)
- [Commits](nedbat/coveragepy@7.5.3...7.6.4)

---
updated-dependencies:
- dependency-name: coverage
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

server/requirements.txt

@@ -8,7 +8,7 @@ wooper==0.4.4
 requests
 requests-mock==1.12.1
 icalendar>=4.0.3,<5.1
-coverage==7.5.3
+coverage==7.6.4
 deepdiff
 coveralls
 mock