Update tbump requirement from ~=6.6.0 to ~=6.7.0 (#5600)

Updates the requirements on [tbump](https://github.com/dmerejkowsky/tbump) to permit the latest version.
- [Release notes](https://github.com/dmerejkowsky/tbump/releases)
- [Changelog](https://github.com/dmerejkowsky/tbump/blob/main/Changelog.rst)
- [Commits](your-tools/tbump@v6.6.0...v6.7.0)

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

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

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Pierre Sassoulas <[email protected]>
Co-authored-by: Daniël van Noord <[email protected]>

Author: 3 people

requirements_test.txt

@@ -3,7 +3,7 @@
 coveralls~=3.3
 coverage~=6.3
 pre-commit~=2.17
-tbump~=6.6.0
+tbump~=6.7.0
 contributors-txt>=0.7.3
 pyenchant~=3.2
 pytest-cov~=3.0