[core] Add SDK_VERSION

lib/modules/core/firebase.js

@@ -7,6 +7,7 @@ import { NativeModules } from 'react-native';
 import APPS from '../../utils/apps';
 import INTERNALS from '../../utils/internals';
 import App from './firebase-app';
+import VERSION from '../../version';
 
 // module imports
 import { statics as AdMobStatics, MODULE_NAME as AdmobModuleName } from '../admob';
@@ -112,6 +113,14 @@ class Firebase {
   get apps(): Array<App> {
     return APPS.apps();
   }
+
+  /**
+   * The current SDK version.
+   * @return {string}
+   */
+  get SDK_VERSION(): string {
+    return VERSION;
+  }
 }
 
 export default new Firebase();