[skip changelog] Fix test workflow not running when editing docs

[silvanocerza]

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So I've investigated the issue about the CI skip and the required Checks to merge PRs, I've made some tests in a separate repo.
In the test.yaml I've added the following config:

    paths-ignore:
      - "docs/**"
      - ".github/workflows/docs.yaml"

Both when pushing on master and PRs creation if only docs.yaml or anything inside the docs folder is modified the Workflow is not run at all.

We discovered that this is an issue because the repo is configured to require the 3 checks generated by the test-matrix job to merge a PR.

So I tried to skip conditionally the whole job test-matrix, problem is that the required checks are not on test-matrix but on test-matrix (ubuntu-latest), test-matrix (windows-latest) and test-matrix (macOS-latest); so GH still expects those checks.

Easy you might say, set test-matrix as required so we can skip the whole job. Nope, can't do because if the matrix is actually run the test-matrix check is never run.

So the only solution that I've come up is to skip every single step in test-matrix job, so that it's as if the whole test matrix is run, this way GH is happy because checks are passing.

This is the repo I've used for testing: https://github.com/silvanocerza/nodenode

We discussed several solutions but decided to keep it simple and avoid workarounds that might be hard to understand in the future, therefore we remove the paths-ignore for the test workflow and run the whole test matrix in any case.

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