ci: fix git tag matching

Author: marekvospel

.github/workflows/docker.yaml

@@ -40,8 +40,9 @@ jobs:
           flavor: |
             latest=false
           tags: |
-            type=ref,value=latest,event=tag
+            type=raw,value=latest,enable=${{ startsWith(github.ref, 'refs/tags/') }}
             type=edge,value=edge
+            type=match,pattern=workshop-bot-v(.*),group=1
             type=ref,event=pr
             type=sha
           labels: