act does not support matrix variables with "-" in their names, GitHub does

[adamtheturtle]

I had:

      matrix:
        python-version: [3.7, 3.8]

and

    steps:
      - uses: actions/checkout@v2
      - name: "Set up Python"
        uses: actions/setup-python@v1
        with:
          python-version: ${{ matrix.python-version }}

This works on GitHub but act shows:

ERRO[0004] Unable to interpolate string '${{ matrix.python-version }}' - [ReferenceError: 'version' is not defined] 

[justincy]

Related: #315

[cdb]

@adamtheturtle - this looks like it was fixed just a couple days ago in 0.2.12 #287 (comment)

[adamtheturtle]

Thank you.