Try improving renovate issues with Maven Central rate limiting (#7667)

* Try improving renovate issues with Maven Central rate limiting

Try not to make too many concurrent requests to Maven Central

The logs display rate limit responses followed by OK responses, which could mean we're hammering the Maven Central repo with too many concurrent requests

* Try not hitting Maven Central for `androidx` packages

.github/renovate.json5

@@ -10,7 +10,21 @@
     "gradle",
   ],
   "minimumReleaseAge": "7 days",
+  "hostRules": [
+    {
+      "matchHost": "https://repo1.maven.org/maven2/",
+      "concurrentRequestLimit": 4,
+      "maxRequestsPerSecond": 4,
+    }
+  ],
   "packageRules": [
+    {
+      "matchPackageNames": [
+          "/^androidx.\.*/"
+      ],
+      "groupName": "androidx",
+      "registryUrls": [ "https://dl.google.com/android/maven2/" ],
+    },
     {
       "matchPackageNames": [
         "org.matrix.rustcomponents:sdk-android",