typo in roundcube download URL

see https://github.com/mail-in-a-box/mailinabox/commit/8e0967dd8e2ecce6a1092deaca7241a6d927ae1e#commitcomment-7940724

setup/webmail.sh

@@ -41,7 +41,7 @@ fi
 if [ $needs_update == 1 ]; then
 	echo installing roudcube webmail $VERSION...
 	rm -f /tmp/roundcube.tgz
-	wget -qO /tmp/roundcube.tgz http://downloads.sourceforge.net/project/roundcubemail/roundcubemail/1.0.2/roundcubemail-$VERSION.tar.gz
+	wget -qO /tmp/roundcube.tgz http://downloads.sourceforge.net/project/roundcubemail/roundcubemail/$VERSION/roundcubemail-$VERSION.tar.gz
 	tar -C /usr/local/lib -zxf /tmp/roundcube.tgz
 	mv /usr/local/lib/roundcubemail-$VERSION/ /usr/local/lib/roundcubemail
 	rm -f /tmp/roundcube.tgz