Fix memory check script so it works in Debian Bullseye

3 jobs for upgrade-monitoring-to-bullseye in 14 minutes and 12 seconds (queued for 3 seconds)
Status Name Job ID Coverage
  Check Code
passed check-code #222678
docker

00:01:13

 
  Tests
passed compile-profiles #222679
docker

00:12:59

passed enc-test #222680

00:00:30