Update coverage requirement from ~=7.2 to ~=7.4

Updates the requirements on [coverage](https://github.com/nedbat/coveragepy) to permit the latest version.
- [Release notes](https://github.com/nedbat/coveragepy/releases)
- [Changelog](https://github.com/nedbat/coveragepy/blob/master/CHANGES.rst)
- [Commits](nedbat/coveragepy@7.2.0...7.4.0)

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

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

requirements_test.txt

@@ -1,6 +1,6 @@
 -r requirements_test_pre_commit.txt
 -r requirements_test_min.txt
-coverage~=7.2
+coverage~=7.4
 pytest-cov~=4.1
 pytest-profiling~=1.7
 pytest-xdist~=3.5