Bump pyyaml from 5.1.2 to 5.4 in /test (#156)

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] <[email protected]>

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

Author: dependabot[bot]

test/upstream-requirements-py27.txt

@@ -60,7 +60,7 @@ pytest-xdist==1.30.0
 python-dateutil==2.8.0
 python-jose==3.0.1
 pytz==2019.3
-PyYAML==5.1.2
+PyYAML==5.4
 requests==2.22.0
 responses==0.10.6
 rsa==4.5

test/upstream-requirements-py37.txt

@@ -48,7 +48,7 @@ pytest-xdist==1.30.0
 python-dateutil==2.8.0
 python-jose==3.0.1
 pytz==2019.3
-PyYAML==5.1.2
+PyYAML==5.4
 requests==2.22.0
 responses==0.10.6
 rsa==4.5