even more renovate shenanigans

infrastructure/external-dns/renovate.json

@@ -2,7 +2,13 @@
   "hostRules": [
     {
       "hostType": "docker",
-      "matchHost": "git.kluster.moll.re",
+      "matchHost": "git.kluster.moll.re"
+    }
+  ],
+  "packageRules": [
+    {
+      "matchDatasources": ["docker"],
+      "versioning": "regex:^(?<major>\\d+)\\.(?<minor>\\d+)\\.(?<patch>\\d+)-build.(?<build>\\d+)$"
     }
   ]
 }