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] <[email protected]>

Author: dependabot[bot]

requirements.txt

@@ -5,7 +5,7 @@ ntplib==0.3.4
 Twisted==20.3.0
 colorlog==3.1.0
 simplejson==3.11.1
-PyYAML==5.3.1
+PyYAML==5.4
 grpcio-tools>=1.9.0,<=1.50.0
 grpcio>=1.9.0,<=1.50.0
 google-api-python-client==1.8.3