Hardcode the bundle identifier

Author: Widcket

auth0_flutter/example/ios/Runner/Info.plist

@@ -11,7 +11,7 @@
 	<key>CFBundleExecutable</key>
 	<string>$(EXECUTABLE_NAME)</string>
 	<key>CFBundleIdentifier</key>
-	<string>$(PRODUCT_BUNDLE_IDENTIFIER)</string>
+	<string>com.auth0.auth0FlutterExample</string>
 	<key>CFBundleInfoDictionaryVersion</key>
 	<string>6.0</string>
 	<key>CFBundleName</key>