chore(deps): update coverage[toml] requirement from ~=7.2 to ~=7.4

Updates the requirements on [coverage[toml]](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@7.3.0...7.4.0)

---
updated-dependencies:
- dependency-name: coverage[toml]
  dependency-type: direct:production
...

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

requirements-testing.txt

@@ -1,5 +1,5 @@
 coverage[toml] ~= 7.2; python_version == '3.7'
-coverage[toml] ~= 7.3; python_version > '3.7'
+coverage[toml] ~= 7.4; python_version > '3.7'
 pytest ~= 7.4
 pytest-cov ~= 4.1
 pytest-timeout ~= 2.2