Update yamllint requirement from ~=1.27 to ~=1.28

Updates the requirements on [yamllint](https://github.com/adrienverge/yamllint) to permit the latest version.
- [Release notes](https://github.com/adrienverge/yamllint/releases)
- [Changelog](https://github.com/adrienverge/yamllint/blob/master/CHANGELOG.rst)
- [Commits](adrienverge/yamllint@v1.27.0...v1.28.0)

---
updated-dependencies:
- dependency-name: yamllint
  dependency-type: direct:development
...

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

requirements-dev.txt

@@ -4,4 +4,4 @@ packaging==21.3
 pre-commit~=2.20
 PyGithub~=1.55
 pyupgrade~=2.37
-yamllint~=1.27
+yamllint~=1.28