Convert malformed-yaml action to Python

[tamsinforbes]

👀 Purpose

• Convert the malformed-yaml action from 💎 Ruby to 🐍 Python

♻️ What's changed

• ♻️ Created action python-malformed-yaml using Python and Docker with the same functionality as malformed-yaml (if malformed YAML PR fails, changes requested, if good YAML PR OK, if no YAML changes PR OK).
• ✨ Output the error message from the malformed YAML to make it easier to fix.
• 🧪 Set up pytest test for main.py functions to detect malformed yaml files
• 🧪 Set up workflow to run the test

📝 Notes

• Use requirements.txt over Pipfile as there were problems running Pipfile in Docker container; can revisit
  -To Do
• Change name of action to malformed-yaml to replace Ruby version
• Create a new release v18.0.0 documenting breaking changes.

[github-actions]

😱 The following malformed YAML files and related errors were found:

python-malformed-yaml/test/test_yaml_files/bad.yaml:
while scanning a quoted scalar
in "python-malformed-yaml/test/test_yaml_files/bad.yaml", line 2, column 14
found unexpected end of stream
in "python-malformed-yaml/test/test_yaml_files/bad.yaml", line 3, column 1

python-malformed-yaml/test/test_yaml_files/bad.yml:
while scanning a quoted scalar
in "python-malformed-yaml/test/test_yaml_files/bad.yml", line 2, column 6
found unexpected end of stream
in "python-malformed-yaml/test/test_yaml_files/bad.yml", line 3, column 1

🥺 Please correct them and resubmit this PR.

[github-actions]

😱 The following malformed YAML files and related errors were found:

python-malformed-yaml/test/test_yaml_files/bad.yaml:
while scanning a quoted scalar
in "python-malformed-yaml/test/test_yaml_files/bad.yaml", line 2, column 14
found unexpected end of stream
in "python-malformed-yaml/test/test_yaml_files/bad.yaml", line 3, column 1

python-malformed-yaml/test/test_yaml_files/bad.yml:
while scanning a quoted scalar
in "python-malformed-yaml/test/test_yaml_files/bad.yml", line 2, column 6
found unexpected end of stream
in "python-malformed-yaml/test/test_yaml_files/bad.yml", line 3, column 1

🥺 Please correct them and resubmit this PR.

[github-actions]

😱 The following malformed YAML files and related errors were found:

python-malformed-yaml/test/test_yaml_files/bad.yaml:
while scanning a quoted scalar
in "python-malformed-yaml/test/test_yaml_files/bad.yaml", line 2, column 14
found unexpected end of stream
in "python-malformed-yaml/test/test_yaml_files/bad.yaml", line 3, column 1

python-malformed-yaml/test/test_yaml_files/bad.yml:
while scanning a quoted scalar
in "python-malformed-yaml/test/test_yaml_files/bad.yml", line 2, column 6
found unexpected end of stream
in "python-malformed-yaml/test/test_yaml_files/bad.yml", line 3, column 1

🥺 Please correct them and resubmit this PR.

[jasonBirchall]

As much as I'd like to, I don't think we can remove the code-formatter yet.

[tamsinforbes]

Then I think it will fail every time, as the code formatter notices malformed yamls

[tamsinforbes]

See here: the code formatter notices the malformed YAML test files, can't fix them and fails the PR.

[jasonBirchall]

This is great. Just need to add format-code back in.