Update readme.md

Author: willmcgugan

readme.md

@@ -92,6 +92,7 @@ Credits
 
 * [Will McGugan](https://github.com/willmcgugan)
 * [Martin Larralde](https://github.com/althonos) for TarFS
+* [Giampaolo](https://github.com/gpcimino) for `copy_if_newer` and ftp fixes.
 
 PyFilesystem2 owes a massive debt of gratitude to the following
 developers who contributed code and ideas to the original version.