fix(actions): add sigstore/cosign

actions.json

@@ -114,6 +114,24 @@
       "matchPackageNames": [
         "peter-evans/dockerhub-description"
       ]
+    },
+    {
+      "addLabels": [
+        "renovate/automerge",
+        "renovate/github-action"
+      ],
+      "automerge": true,
+      "enabled": true,
+      "matchDatasources":[
+        "github-tags"
+      ],
+      "matchPackageNames": [
+        "sigstore/cosign"
+      ],
+      "matchUpdateTypes": [
+        "minor",
+        "patch"
+      ]
     }
   ]
 }