Update coverage requirement from <7.0.0,>=6.2.2 to >=6.2.2,<8.0.0

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@6.3...7.4.1)

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

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

pyproject.toml

@@ -71,7 +71,7 @@ dev = [
   "blackdoc==0.3.9",
   "bump-my-version>=0.17.1",
   "coverage",
-  "coverage>=6.2.2,<7.0.0",
+  "coverage>=6.2.2,<8.0.0",
   "coveralls>=3.3.1",
   "flake8-alphabetize>=0.0.21",
   "flake8-rst-docstrings>=0.3.0",