Bump pyyaml from 3.13 to 5.4

Bumps [pyyaml](https://github.com/yaml/pyyaml) from 3.13 to 5.4.
- [Release notes](https://github.com/yaml/pyyaml/releases)
- [Changelog](https://github.com/yaml/pyyaml/blob/master/CHANGES)
- [Commits](yaml/pyyaml@3.13...5.4)

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

setup.py

@@ -131,7 +131,7 @@
         "Flask-WTF==0.12",
         "typing",
         "click==6.7",
-        "pyyaml==3.13",
+        "pyyaml==5.4",
         "requests",
         "future",
         "lit==0.11.1",