added summary of upgradable packages in "update" command

pman.sh

@@ -87,6 +87,13 @@ case "$command_args" in
     if [ "$command" = "pacman" ]; then
       su_needed=true
     fi
+    execute_command "${@}"
+
+    su_needed=false
+    command_args="-Qu"
+    echo
+    echo "$(execute_command "${@}" | wc -l) packages are available for update"
+    exit 0
     ;;
   "upgradable")
     command_args="-Qu"