Add SkiaSharp dependency group

Author: jjonescz

renovate.json

@@ -2,5 +2,11 @@
   "extends": [
     "config:base"
   ],
-  "ignorePaths": ["**/examples/**"]
+  "ignorePaths": ["**/examples/**"],
+  "packageRules": [
+    {
+      "matchPackagePrefixes": ["SkiaSharp"],
+      "groupName": "SkiaSharp"
+    }
+  ]
 }