ci/qa: Limit the memory used by Go during tests

Github runners are limited and so we may be hit hard by errors that will
stop the runners.

So limit the go memory usage to avoid this to happen.

See: actions/runner-images#6680

.github/workflows/qa.yaml

@@ -10,6 +10,10 @@ on:
 env:
   DEBIAN_FRONTEND: noninteractive
   GO_TESTS_TIMEOUT: 20m
+  # Prevents github to stop the job, we've 16GB of RAM, so let's limit the go usage at least.
+  # See: https://docs.github.com/en/actions/writing-workflows/choosing-where-your-workflow-runs/choosing-the-runner-for-a-job#choosing-github-hosted-runners
+  GOMEMLIMIT: 5120MiB
+
   apt_deps: >-
     libpam-dev
     libglib2.0-dev