Renovate: try another way to ignore monorepo-npm-unsupported

renovate.json5

@@ -18,12 +18,6 @@
     "github>ecraig12345/renovate-config:groupFixtureUpdates"
   ],
 
-  "ignorePaths": [
-    "**/node_modules/**",
-    // This lock file is generated by npm 6 (renovate always uses 8) and has no deps
-    "**/__fixtures__/monorepo-npm-unsupported"
-  ],
-
   // Use this label on all PRs
   "labels": ["renovate"],
 
@@ -31,6 +25,13 @@
   "prHourlyLimit": 5,
 
   "packageRules": [
+    {
+      // Overrides for the fixture dependencies group:
+      // ignore a package with a lock file generated by npm 6 (renovate always uses 8,
+      // and the package doesn't actually have any deps)
+      "groupName": "fixture dependencies",
+      "matchPaths": ["**/__fixtures__/!(monorepo-npm-unsupported)/package.json"]
+    },
     // Limit upgrades of packages that were converted to ESM in newer versions
     // (the repo and in particular jest isn't set up for ESM yet)
     { "matchPackageNames": ["find-up"], "allowedVersions": "<6.0.0" },