docs: point npm homepage to GMI open-source page (#50)

Author: mikolajlehman

package/package.json

@@ -68,7 +68,7 @@
   "bugs": {
     "url": "https://github.com/gmi-software/react-native-better-maps/issues"
   },
-  "homepage": "https://github.com/gmi-software/react-native-better-maps#readme",
+  "homepage": "https://gmi.software/open-source",
   "author": "gmi.software",
   "license": "MIT",
   "publishConfig": {