Build a standard GitHub action that reacts on commits and Pull Requests (PRs) on a given GitHub repository, called FOSSA GitHub Action.

Every time that a commit is pushed or a PR is merged, the FOSSA GitHub Action is triggered, the action

1. Reads a .fossa-licenses.yaml file, containing
1. A list of SPDX IDs called "compatibleLicenses"
2. A list of SPDX IDs called "incompatibleLicenses"
3. A list of strings called "whitelistedLibraries"
4. ... (more will come after the MVP)
2. Reads the FOSSA_API_KEY (encrypted) environment variable, containing the key of FINOS account
3. Invokes "fossa init" and "fossa report licenses --json", generating a JSON payload with all library and license definitions
4. Parses the generated JSON (on step 5) and builds a report with
1. List of libraries with compatible licenses (and the compatible license that applies)
2. List of libraries with incompatible licenses
3. List of libraries with unknown licenses 
5. Format the report in Markdown and post on a new github issue. If the action was triggered by a PR, the check will succeed or fail based on the amount of incompatible /unknown licenses found