Update renovate.json

Apparently formatting json with buildifier results in something that is not json. Who would have thought.
diff --git a/renovate.json b/renovate.json
index 35d60f6..ee8c906 100644
--- a/renovate.json
+++ b/renovate.json
@@ -1,5 +1,5 @@
 {
     "extends": [
-        "config:base",
-    ],
+        "config:base"
+    ]
 }