Bump pyyaml from 5.3.1 to 5.4 (#76)

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]>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

requirements.txt

@@ -7,4 +7,4 @@ psycopg2-binary==2.8.4
 dj-database-url==0.5.0
 gunicorn==20.0.4
 whitenoise==5.0.1
-PyYAML==5.3.1
+PyYAML==5.4