makepkg: drop sudo permissions after use

Add the -k parameter to the sudo call to prevent caching of credientials.
This would (potentailly) stop a rogue sudo use within a PKGBUILD.

Signed-off-by: Allan McRae <allan@archlinux.org>

scripts/makepkg.sh.in

@@ -241,7 +241,7 @@ run_pacman() {
 				cmd=("${PACMAN_AUTH[@]}" "${cmd[@]}")
 			fi
 		elif type -p sudo >/dev/null; then
-			cmd=(sudo "${cmd[@]}")
+			cmd=(sudo -k "${cmd[@]}")
 		else
 			cmd=(su root -c "$cmdescape")
 		fi