Bump pyyaml from 5.4.1 to 6.0

Bumps [pyyaml](https://github.com/yaml/pyyaml) from 5.4.1 to 6.0.
- [Release notes](https://github.com/yaml/pyyaml/releases)
- [Changelog](https://github.com/yaml/pyyaml/blob/master/CHANGES)
- [Commits](yaml/pyyaml@5.4.1...6.0)

---
updated-dependencies:
- dependency-name: pyyaml
  dependency-type: direct:development
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

requirements_dev.txt

@@ -4,7 +4,7 @@ flake8==4.0.1
 mock==3.0.5
 pip==21.3.1
 pytest==4.4.1
-PyYAML==5.4.1
+PyYAML==6.0
 Sphinx==4.3.1
 tox==3.13.2
 watchdog==0.9.0