action: Use $GITHUB_OUTPUT instead of deprecated ::set-output

Author: dalcinl

.github/workflows/ci.yml

@@ -57,10 +57,14 @@ jobs:
       uses: actions/checkout@v3
 
     - name: Setup MPI
+      id:   setup-mpi
       uses: ./
       with:
         mpi: ${{ matrix.mpi }}
 
+    - name: Show MPI name
+      run:  echo "${{ steps.setup-mpi.outputs.mpi }}"
+
     - name: Show MPI info
       run:  mpichversion
       if:   ${{ matrix.mpi == 'mpich' }}

setup-mpi.sh

@@ -64,7 +64,7 @@ case $(uname) in
         ;;
 esac
 
-echo "::set-output name=mpi::${MPI}"
+echo "mpi=${MPI}" >> $GITHUB_OUTPUT
 
 case $MPI in
     mpich)