Update docker.yml

.github/workflows/docker.yml

@@ -59,13 +59,11 @@ jobs:
         uses: docker/metadata-action@v5
         with:
           images: archivebox/archivebox,nikisweeting/archivebox
-          flavor: |
-              latest=auto
           tags: |
               type=ref,event=branch
               type=semver,pattern={{version}}
               type=semver,pattern={{major}}.{{minor}}
-              type=sha
+              type=raw,value=latest,enable={{is_default_branch}}
       
       - name: Build and push
         id: docker_build