Add 6.x branch

Author: yusinto

.ldrelease/config.yml

@@ -4,6 +4,11 @@ repo:
   public: react-native-client-sdk
   private: react-native-client-sdk-private
 
+branches:
+  - name: main
+    description: 7.x
+  - name: 6.x
+
 publications:
   - url: https://www.npmjs.com/package/launchdarkly-react-native-client-sdk
     description: npm