Update README

Author: corny

README.md

@@ -21,7 +21,7 @@ This tool is meant to be used to download CC0 licenced content, we do not suppor
 
 ### Install via go get
 
-Please ensure you have installed Go 1.18 or later.
+Please ensure you have installed Go 1.21 or later.
 
 ```shell
 go get github.com/kkdai/youtube/v2