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>

requirements-dev.txt

@@ -33,7 +33,7 @@ pyparsing==2.4.7
 pytest-cov==2.10.1
 pytest==6.1.2
 pytz==2020.4
-pyyaml==5.3.1
+pyyaml==5.4
 regex==2020.11.13
 releases==1.6.3
 requests==2.25.0