⬆️ Update coverage requirement from <7.7,>=7.2.7 to >=7.2.7,<7.9 (#62)

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@7.2.7...7.8.0)

---
updated-dependencies:
- dependency-name: coverage
  dependency-version: 7.8.0
  dependency-type: direct:development
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

dev-requirements.txt

@@ -1,3 +1,3 @@
 requests>=2.10
 pytest>=2.8.0,<=8.3.4
-coverage>=7.2.7,<7.7
+coverage>=7.2.7,<7.9