chore: add SUC group to renovate config

.github/renovate.json5

@@ -68,6 +68,16 @@
       },
       "separateMinorPatch": true
     },
+    {
+      "description": "System Upgrade Controller Group",
+      "groupName": "System Upgrade Controller",
+      "matchPackagePatterns": ["rancher/system-upgrade-controller"],
+      "matchDatasources": ["docker", "github-releases"],
+      "group": {
+        "commitMessageTopic": "{{{groupName}}} group"
+      },
+      "separateMinorPatch": true
+    },
     // custom versioning
     {
       "description": "Use custom versioning for k3s",