ci: Replace deprecated GHA set-output command

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

.github/workflows/check.yaml

@@ -35,7 +35,7 @@ jobs:
       - name: Get pip cache dir
         id: pip-cache
         run: |
-          echo "::set-output name=dir::$(pip cache dir)"
+          echo "dir=$(pip cache dir)" >> $GITHUB_OUTPUT
       - name: Persistent Github pip cache
         uses: actions/cache@v3
         with: