Update gravity.sh grammer

Small grammer issue, stayed being past tense, along with unchanged is redundant. With this change we are saying "We checked to see if the list updated, and there was no update so it stays the same"

Signed-off-by: Tadgh Henry <47073445+tadghh@users.noreply.github.com>

gravity.sh

@@ -488,7 +488,7 @@ compareLists() {
       echo "  ${INFO} List has been updated"
       database_adlist_status "${adlistID}" "1"
     else
-      echo "  ${INFO} List stayed unchanged"
+      echo "  ${INFO} List stays unchanged"
       database_adlist_status "${adlistID}" "2"
     fi
   else