Bump pyyaml from 5.1.2 to 5.4

Bumps [pyyaml](https://github.com/yaml/pyyaml) from 5.1.2 to 5.4.
- [Release notes](https://github.com/yaml/pyyaml/releases)
- [Changelog](https://github.com/yaml/pyyaml/blob/master/CHANGES)
- [Commits](yaml/pyyaml@5.1.2...5.4)

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

Author: dependabot[bot]

requirements.txt

@@ -19,7 +19,7 @@ PyMySQL==0.9.3
 PyNaCl==1.4.0
 pyparsing==2.4.7
 pysolr==3.8.1
-PyYAML==5.1.2
+PyYAML==5.4
 readme-renderer==26.0
 requests==2.22.0
 requests-toolbelt==0.9.1

setup.py

@@ -25,7 +25,7 @@
             'idna==2.8',
             'PyMySQL',
             'pysolr==3.8.1',
-            'PyYAML==5.1.2',
+            'PyYAML==5.4',
             'requests==2.22.0',
             'tqdm==4.35.0',
             'urllib3==1.25.3',