Refactor Github Action per b/485167538

Author: benknutson-google

.github/workflows/deploy_versioned_docs.yaml

@@ -35,7 +35,9 @@ jobs:
           ref: ${{ github.event.release.tag_name }}
 
       - name: Get Version from Release Tag
-        run: echo "VERSION=${{ github.event.release.tag_name }}" >> $GITHUB_ENV
+        run: echo "VERSION=${GITHUB_EVENT_RELEASE_TAG_NAME}" >> $GITHUB_ENV
+        env:
+          GITHUB_EVENT_RELEASE_TAG_NAME: ${{ github.event.release.tag_name }}
 
       - name: Setup Hugo
         uses: peaceiris/actions-hugo@75d2e84710de30f6ff7268e08f310b60ef14033f # v3