Run github actions depending on path

[surister]

Right now any PR triggers a full run of tests, for both python and javascript, ideally we should only ran python tests if the python target changes for example.

https://stackoverflow.com/questions/63822219/how-to-run-github-actions-workflow-only-if-the-pushed-files-are-in-a-specific-fo

[amotl]

Good idea. Please see cratedb-examples' workflows for more inspirations and blueprints.