Update coverage requirement from ==6.* to ==7.*

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](coveragepy/coveragepy@6.0b1...7.0.0)

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

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

Author: dependabot[bot]

requirements.test.txt

@@ -1,3 +1,3 @@
 pytest==7.*
-coverage==6.*
+coverage==7.*
 pytest-asyncio==0.*