check for sudo via 'command -v' instead of dkpg-query

pihole

@@ -17,7 +17,7 @@ if [[ ! $EUID -eq 0 ]];then
 	#echo "::: Sudo will be used for this tool."
   # Check if it is actually installed
   # If it isn't, exit because the pihole cannot be invoked without privileges.
-  if [[ $(dpkg-query -s sudo) ]];then
+  if [ -x "$(command -v sudo)" ];then
 		export SUDO="sudo"
   else
     echo "::: Please install sudo or run this as root."