JSON validation GitHub action

[timpulver]

We should set up a GitHub Action to validate the JSON file on every pull request.

• validate that JSON file is valid JSON file
• validate that schema of JSON file is valid

[michaelGregoire]

I implemented a validation script. However, in order to validate the json, the file needs to be required. If there are syntax errors in the file, an error is thrown. So, the script is not directly validating the json syntax, but it does do the trick. I'll let you close this ticket or not, if you feel that my implementation needs a bit of work.

[timpulver]

Great @michaelGregoire
Looks good.

Did you use GitHub Actions before?

A good workflow would be:

On every new pull request to master:
  run validation script
  if it does not throw an error
    approve pull request
  if error is thrown:
    reject pull request