Fix gradle workflow (#9716)

Author: sarahchen6

.github/workflows/update-gradle-dependencies.yaml

@@ -47,7 +47,7 @@ jobs:
       - name: Pick a branch name
         if: steps.check-changes.outputs.commit_changes == 'true'
         id: define-branch
-        run: echo "BRANCH_NAME=ci/update-gradle-dependencies-$(date +'%Y%m%d')" >> $GITHUB_ENV
+        run: echo "branch=ci/update-gradle-dependencies-$(date +'%Y%m%d')" >> $GITHUB_OUTPUT
       - name: Commit changes
         if: steps.check-changes.outputs.commit_changes == 'true'
         id: create-commit
@@ -76,7 +76,7 @@ jobs:
           echo -e "This PR updates the Gradle dependencies. ⚠️ Don't forget to squash commits before merging. ⚠️\n\n- [ ] Update PR title if a code change is needed to support one of those new dependencies" | \
             gh pr create --title "Update Gradle dependencies" \
             --base master \
-            --head $BRANCH_NAME \
+            --head ${{ steps.define-branch.outputs.branch }} \
             --label "tag: dependencies" \
             --label "tag: no release notes" \
             --body-file -