Bump pyyaml from 5.3.1 to 5.4 (#3383)

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](https://github.com/yaml/pyyaml/compare/5.3.1...5.4)

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

requirements/requirements.txt

@@ -19,7 +19,7 @@ django-ratelimit==3.0.1
 easy-thumbnails==2.5
 python-decouple==3.1
 psycopg2-binary==2.8.6
-pyyaml==5.3.1
+pyyaml==5.4
 pytz==2019.3
 python-magic==0.4.15
 unipath==1.1

setup.py

@@ -29,7 +29,7 @@ install_requires = [
     'easy-thumbnails==2.5',
     'python-decouple==3.1',
     'psycopg2-binary==2.7.6.1',
-    'pyyaml==4.2b1',
+    'pyyaml==5.4',
     'pytz==2018.9',
     'python-magic==0.4.15',
     'unipath==1.1',