Cancel script if not windows

added return to cancel installation of the script if not windows, after displaying a message to user

contrib/OpenInExplorer.lua

@@ -42,6 +42,7 @@ if dt.configuration.running_os == "windows" then
 	proper_install = true
 else
 	dt.print_error('OpenInExplorer plug-in only supports Windows OS at this time')
+	return
 end
 
 -- FUNCTION --