Update README.md

Updating the correct url.

Author: mdmush

README.md

@@ -4,7 +4,7 @@ wkh237's last Github activity was in September 2017, and he has not reacted to e
 
 The owners of this fork have agreed to maintain this package:
 
-https://github.com/joltup/react-native-fetch-blob
+https://github.com/joltup/rn-fetch-blob
 
 That means issues and PRs should be posted there.