[CI] Add annotation to workflow pod

Still running into the issue where processes in the workflow container are
dying. Not convinced this is the problem now, but doesn't hurt to add the
annotation.

premerge/linux_container_pod_template.yaml

@@ -1,3 +1,6 @@
+metadata:
+  annotations:
+    cluster-autoscaler.kubernetes.io/safe-to-evict: "false"
 spec:
   tolerations:
     - key: "premerge-platform"