Update installation-windows.md

Corrected Chameleon version number in 'composer require' command.

Author: felis-margarita

docs/installation-windows.md

@@ -43,7 +43,7 @@ Here is a step by step procedure for Windows:
     command line window will open.
 
 5.  On the command line run the command
-    `composer require "mediawiki/chameleon-skin:~3.0"`
+    `composer require "mediawiki/chameleon-skin:~5.0"`
 
 6.  If there were no errors, close the command line window.