Auto versioning pipeline fails from fork

[fmilthaler]

Failed pipeline: https://github.com/fmilthaler/FinQuant/actions/runs/5730526086/job/15530536877?pr=120

      - name: Check out code
        uses: actions/checkout@v3
        with:
          ref: ${{ github.head_ref }}
          fetch-depth: 0

the above causes the failure. the below works on forks:

      - name: Checkout code
        uses: actions/checkout@v3