Run CI on pull request and on push

[bthomee]

The on: push does not always trigger on new commits pushed to a branch. This change adds a specific on: pull_request.

[mathbunnyru]

At the bottom of this file, instead of having if: ${{ github.ref_type == 'branch' && github.ref_name == github.event.repository.default_branch }} let's write it much simpler: if: ${{ github.event_name == 'push' }}

[mathbunnyru]

Please, see my comment above.

Also, please make it work for forks - you shouldn't login, so it should also be under if

[bthomee]

Please, see my comment above.

Also, please make it work for forks - you shouldn't login, so it should also be under if

Good call, done.

[bthomee]

Please, see my comment above.
Also, please make it work for forks - you shouldn't login, so it should also be under if

Good call, done.

Regarding forks... let me add the same logic here as we have in the rippled repo.