Add support for Wagtail 4

[engineervix]

Support ticket: https://projects.torchbox.com/projects/support-team/tickets/613

This allows usage and tests for latest Wagtail and Django versions.

[engineervix]

The CI job still failed even after 1ad3bdd.

Looks like the solution is to add continue-on-error: ${{ matrix.experimental }} as part of the steps, like this:

    steps:
    - uses: actions/checkout@v1
    - name: Set up Python ${{ matrix.python-version }}
      uses: actions/setup-python@v1
      with:
        python-version: ${{ matrix.python-version.version }}
    - name: Install dependencies
      run: |
        python -m pip install --upgrade pip tox
    - name: Test with tox
      env:
        TEST_DB_NAME: wagtail_factories
        TEST_DB_USER: wagtail_factories
        TEST_DB_PASSWORD: secret
        TOX_ENV: "py${{ matrix.python-version.tox }}-django${{ matrix.django }}-wagtail${{ matrix.wagtail }}-factoryboy${{ matrix.factoryboy }}"
      continue-on-error: ${{ matrix.experimental }}
      run: |
        tox -e $TOX_ENV

[zerolab]

the test aginst wagtailmain should be a nightly task, imho. At least until GitHub add proper support for "allow failure" and the UI is updated accordingly. Even with "continue-on-error" the CI task would show as failed

https://github.com/wagtail/wagtail/wiki/Nightly-testing-of-official-plugins

[engineervix]

the test aginst wagtailmain should be a nightly task, imho. At least until GitHub add proper support for "allow failure" and the UI is updated accordingly. Even with "continue-on-error" the CI task would show as failed

https://github.com/wagtail/wagtail/wiki/Nightly-testing-of-official-plugins

Good shout! I have removed tests against wagtailmain in d71f135. I think setting up nightly tests can be done in a separate PR.

[jams2]

Looks good to me, thanks @engineervix