Bump pyyaml from 5.4 to 6.0 in /src

Bumps [pyyaml](https://github.com/yaml/pyyaml) from 5.4 to 6.0.
- [Release notes](https://github.com/yaml/pyyaml/releases)
- [Changelog](https://github.com/yaml/pyyaml/blob/master/CHANGES)
- [Commits](yaml/pyyaml@5.4...6.0)

---
updated-dependencies:
- dependency-name: pyyaml
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

src/Pipfile

@@ -21,7 +21,7 @@ lxml = "==4.6.5"
 mozprocess = "==1.1.0"
 oauth2client = "==4.1.3"
 protobuf = "==3.19.0"
-PyYAML = "==5.4"
+PyYAML = "==6.0"
 redis = "==3.3.11"
 requests = "==2.21.0"
 six = "==1.14.0"