Add Parse Server instance for testing to CI

[mtrezza]

Issue

Tests here are mocked, as no Parse Server instance is running to test against it. This is not optimal:

• requires more effort to write tests
• mocked server behavior may be inaccurate / outdated
• CI does not run against specific version of Parse Server

Suggested Solution

• Set up CI to spin up a Parse Server instance for the current version of Parse Server plus the LTS version.
• Add server test logic to test setup (data cleaning between tests, etc).
• Add Parse Server compatibility matrix to README.

CI example: https://github.com/parse-community/parse-server-s3-adapter/blob/master/.github/workflows/ci.yml

[parse-github-assistant[bot]]

Thanks for opening this issue!

[YBTopaz8]

This will be superb when integrating Live Queries.

Pretty good for release , I'm only in need of UnitTests so as to do a PR

[mtrezza]

If you would like, you could open a PR and use the CI link above as a guideline for how to set this up.