chore(ci): 🛠 setup continuous deployment

[yjaaidi]

🚀 Let's auto-publish everything!

• needs fixing postTargets is running build target in watch mode semver#353

[yjaaidi]

@edbzn do you know why we explicitly specify ref & repository?
It's the initial setup so I can't find the reason in the commits history.
I don't think it's necessary, even for external PRs (i.e. from a fork) so let's remove this and see what happens.

    - name: Checkout all commits
      uses: actions/checkout@v2
      with:
        ref: ${{ github.event.pull_request.head.ref }}
        repository: ${{ github.event.pull_request.head.repo.full_name }}
        fetch-depth: 0