Bump pyyaml from 4.2b1 to 5.4

Bumps [pyyaml](https://github.com/yaml/pyyaml) from 4.2b1 to 5.4.
- [Release notes](https://github.com/yaml/pyyaml/releases)
- [Changelog](https://github.com/yaml/pyyaml/blob/master/CHANGES)
- [Commits](https://github.com/yaml/pyyaml/commits/5.4)

---
updated-dependencies:
- dependency-name: pyyaml
  dependency-type: direct:production
...

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

Author: dependabot[bot]

requirements.txt

@@ -6,7 +6,7 @@ packtrack==1.6
 xmltodict
 flake8
 celery[mongodb]<4.0
-PyYAML==4.2b1
+PyYAML==5.4
 requests==2.20.0
 raven==5.11.1
 newrelic==2.66.0.49