Update README to remove fork information

Removed fork reference from README.

Author: SpringMT

README.md

@@ -7,8 +7,6 @@ Ruby binding for zstd(Zstandard - Fast real-time compression algorithm)
 
 See https://github.com/facebook/zstd
 
-Fork from https://github.com/jarredholman/ruby-zstd.
-
 ## Zstd version
 [v1.5.7](https://github.com/facebook/zstd/tree/v1.5.7)