Update README.md

changed typo

Author: MangaValk

README.md

@@ -4,7 +4,7 @@ YUI Compressor - The Yahoo! JavaScript and CSS Compressor
 The YUI Compressor is a JavaScript compressor which, in addition to removing
 comments and white-spaces, obfuscates local variables using the smallest
 possible variable name. This obfuscation is safe, even when using constructs
-such as 'eval' or 'with' (although the compression is not optimal is those
+such as 'eval' or 'with' (although the compression is not optimal in those
 cases) Compared to jsmin, the average savings is around 20%.
 
 The YUI Compressor is also able to safely compress CSS files. The decision