use $GITHUB_OUTPUT instead of ::set-output (#142)

* use `$GITHUB_OUTPUT` instead of `::set-output`

* upgrade the nightly python version [test-upstream]

Author: keewis

.github/workflows/nightly.yaml

@@ -41,7 +41,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: ["3.11"]
+        python-version: ["3.12"]
 
     outputs:
       artifacts_availability: ${{ steps.status.outputs.ARTIFACTS_AVAILABLE }}
@@ -84,7 +84,7 @@ jobs:
           cd docs
           python -m sphinx -M html -d _build/doctrees -EWT -a . _build/html \
           | tee output-${{ matrix.python-version }}-log || (
-            echo '::set-output name=ARTIFACTS_AVAILABLE::true' && false
+            echo "ARTIFACTS_AVAILABLE=true" >> $GITHUB_OUTPUT && false
           )
 
   report: