Github actions set-output command is deprecated

https://github.blog/changelog/2022-10-11-github-actions-deprecating-save-state-and-set-output-commands/

.github/workflows/base.yml

@@ -36,7 +36,7 @@ jobs:
 
       - name: List 'tests' nox sessions and required python versions
         id: set-matrix
-        run: echo "::set-output name=matrix::$(nox -s gha_list -- -s tests -v)"
+        run: echo "matrix=$(nox -s gha_list -- -s tests -v)" >> $GITHUB_OUTPUT
 
     outputs:
       matrix: ${{ steps.set-matrix.outputs.matrix }}  # save nox sessions list to outputs