chore(deps): update docker/metadata-action action to v5.8.0

Author: renovate[bot]

.github/workflows/docker.yml

@@ -22,7 +22,7 @@ jobs:
 
       - name: Docker meta
         id: meta
-        uses: docker/metadata-action@v5
+        uses: docker/metadata-action@c1e51972afc2121e065aed6d45c65596fe445f3f # v5.8.0
         with:
           images: |
             ghcr.io/clevyr/cloudflare-borgmatic