Bump testfixtures from 6.18.5 to 7.0.0 (#140)

Bumps [testfixtures](https://github.com/Simplistix/testfixtures) from 6.18.5 to 7.0.0.
- [Release notes](https://github.com/Simplistix/testfixtures/releases)
- [Changelog](https://github.com/simplistix/testfixtures/blob/master/CHANGELOG.rst)
- [Commits](simplistix/testfixtures@6.18.5...7.0.0)

---
updated-dependencies:
- dependency-name: testfixtures
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

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

requirements-test.txt

@@ -4,5 +4,5 @@ pylint==2.14.4
 pytest==7.1.2
 pytest-asyncio==0.18.3
 pytest-cov==3.0.0
-testfixtures==6.18.5
+testfixtures==7.0.0
 types-cachetools==5.2.1