build: update renovate to update @angular/dev-infra-private as target: patch

Updating the @angular/dev-infra-private packages should be done on all active
development branches.

Author: josephperrott

renovate.json

@@ -21,9 +21,15 @@
   "packageRules": [
     {
       "packagePatterns": ["^@angular/.*"],
+      "excludePackageNames": ["@angular/dev-infra-private"],
       "groupName": "angular",
       "pinVersions": false
     },
+    {
+      "matchPackageNames": ["@angular/dev-infra-private"],
+      "groupName": "dev-infra",
+      "labels": ["action: merge", "target: patch"]
+    },
     {
       "packagePatterns": ["^@babel/.*"],
       "groupName": "babel",