CI: replace set-output

[gemesa]

Fixes #122

Before:

test run: https://github.com/gemesa/candleLight_fw/actions/runs/4801634233/jobs/8544109203

where test code is:

    - name: Get current date
      id: date
      run: echo "::set-output name=date::$(date +'%Y%m%d')"

    - name: generate short hash
      id: vars
      run: echo "::set-output name=sha_short::$(git rev-parse --short HEAD)"

    - name: print outputs
      run: |
        echo "${{steps.date.outputs.date}}"
        echo "${{steps.vars.outputs.sha_short}}"

After:

test run: https://github.com/gemesa/candleLight_fw/actions/runs/4801616342/jobs/8544066244

where test code is:

    - name: Get current date
      id: date
      run: echo "date=$(date +'%Y%m%d')" >> $GITHUB_OUTPUT

    - name: generate short hash
      id: vars
      run: echo "sha_short=$(git rev-parse --short HEAD)" >> $GITHUB_OUTPUT

    - name: print outputs
      run: |
        echo "${{steps.date.outputs.date}}"
        echo "${{steps.vars.outputs.sha_short}}"

[fenugrec]

Cool, thanks for taking care of this