chore: add badge

Author: vonovak

README.md

@@ -1,5 +1,7 @@
 # react-native-documents
 
+[![npm](https://img.shields.io/badge/npm-@react--native--documents-red?logo=npm)](https://www.npmjs.com/org/react-native-documents)
+
 React Native modules for document picking and viewing.
 
 If this is useful to you, [say thanks](https://github.com/sponsors/vonovak). Your support is greatly appreciated!