Pin androidx dep for minSdk reasons

Bumped to minSdk 23, while we want to test against 21

Author: yschimke

.github/renovate.json

@@ -53,6 +53,13 @@
       ],
       "allowedVersions": "<2.0.0",
       "description": "JDK 11 requirement"
+    },
+    {
+      "matchPackageNames": [
+        "androidx.activity:activity-ktx"
+      ],
+      "allowedVersions": "<=1.11.0",
+      "description": "Android minSdk 23 requirement"
     }
   ]
 }