fix(ci): Prevent duplicate Docker tags in GitHub Actions

- Add latest=false flavor to both backend and frontend jobs
- Fix confusion between latest and latest-frontend tags
- Ensure proper image separation in Docker registries

.github/workflows/release.yml

@@ -66,6 +66,8 @@ jobs:
          id: meta-backend
          uses: docker/metadata-action@v5
          with:
+           flavor: |
+             latest=false
            # list of Docker images to use as base name for tags
            images: |
              elisiariocouto/leggen
@@ -110,6 +112,8 @@ jobs:
          id: meta-frontend
          uses: docker/metadata-action@v5
          with:
+           flavor: |
+             latest=false
            # list of Docker images to use as base name for tags
            images: |
              elisiariocouto/leggen