CI: (deps): Bump coverage from 7.3.4 to 7.4.0 in /ci

Bumps [coverage](https://github.com/nedbat/coveragepy) from 7.3.4 to 7.4.0.
- [Release notes](https://github.com/nedbat/coveragepy/releases)
- [Changelog](https://github.com/nedbat/coveragepy/blob/master/CHANGES.rst)
- [Commits](coveragepy/coveragepy@7.3.4...7.4.0)

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

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

Author: dependabot[bot]

ci/test_requirements.txt

@@ -2,4 +2,4 @@ packaging==23.2
 pytest==7.4.3
 pytest-mpl==0.16.1
 netCDF4==1.6.5
-coverage==7.3.4
+coverage==7.4.0