Auto-convert openapi-schema.yml to openapi.json on commit to master

[tonythomas01]

So right now the docs at http://docs.quarantinehelp.space/#/ is served from https://github.com/Quarantine-Help/quarantine-help-api/tree/master/docs/openapi.json

We have to edit the yaml over an editing service like https://editor.swagger.io/ and then convert it to JSON and update both files. This is kind of sad that we have to maintain two files. How about we only care about the YML file and some script takes care of keeping the JSON in sync ?