Only run auto-indexing Docker build during release

Author: olafurpg

.github/workflows/release-autoindex.yml

@@ -55,3 +55,10 @@ jobs:
             sourcegraph/lsif-typescript:${{ env.PATCH }}
             sourcegraph/lsif-typescript:${{ env.MINOR }}
             sourcegraph/lsif-typescript:${{ env.MAJOR }}
+      - name: Build and push
+        id: docker_build
+        uses: docker/build-push-action@v2
+        with:
+          file: Dockerfile.autoindex
+          push: true
+          tags: sourcegraph/lsif-typescript:autoindex