Bump pyyaml from 5.3.1 to 5.4

Bumps [pyyaml](https://github.com/yaml/pyyaml) from 5.3.1 to 5.4.
- [Release notes](https://github.com/yaml/pyyaml/releases)
- [Changelog](https://github.com/yaml/pyyaml/blob/master/CHANGES)
- [Commits](yaml/pyyaml@5.3.1...5.4)

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

Author: dependabot[bot]

requirements-dev.txt

@@ -16,7 +16,7 @@ pathspec==0.8.1
 pre-commit==2.9.3
 pycodestyle==2.6.0
 pyflakes==2.2.0
-PyYAML==5.3.1
+PyYAML==5.4
 regex==2020.11.13
 requests==2.25.1
 six==1.15.0