Add pre-commit hooks

[turbaszek]

This PR adds pre-commit hooks. Also, I've unified the licenses and added the missing ones.

[turbaszek]

@potiuk @mik-laj @ashb does Github Actions work for this repo? I see that it works on my fork but not here...

[mik-laj]

GitHub actions works for this repository: https://github.com/apache/airflow-on-k8s-operator/actions

[turbaszek]

GitHub actions works for this repository: https://github.com/apache/airflow-on-k8s-operator/actions

I know, in closed PRs you can find my test one. I still don’t know why it doesn’t work on this PR (work on fork).

[mik-laj]

@turbaszek Github Action doesn't work on forks. This PR is from apache repo.

[turbaszek]

@turbaszek Github Action doesn't work on forks. This PR is from apache repo.

Well, it works. I still don't get how the GA works... This works:

on:
  push:
    branches:
      - master
  pull_request:
    branches:
      - master

this not:

on: [push,  pull_request]

[turbaszek]

@mik-laj @potiuk now we've got both yamllint and Github Actions :)

[kaxil]

@turbaszek Github Action doesn't work on forks. This PR is from apache repo.

Well, it works. I still don't get how the GA works... This works:

on:
  push:
    branches:
      - master
  pull_request:
    branches:
      - master

this not:

on: [push,  pull_request]

If the Pull request contains the branch from this repo itself, it would work. If you create a PR from your fork it won't work with GA

[turbaszek]

If the Pull request contains the branch from this repo itself, it would work. If you create a PR from your fork it won't work with GA

Got it! My assumption was that on: [push, pull_request] works always, no matter what. Anyway, we have running static checks on CI! Should we move on? @kaxil @mik-laj