update to drop all capabilities security context (CrunchyData#3305)

[sc-14936]

Author: ValClarkson

config/manager/manager.yaml

@@ -40,6 +40,7 @@ spec:
  value: "registry.developers.crunchydata.com/crunchydata/crunchy-postgres-exporter:ubi8-5.1.2-0"
  securityContext:
  allowPrivilegeEscalation: false
+ capabilities: { drop: [ALL] }
  readOnlyRootFilesystem: true
  runAsNonRoot: true
  serviceAccountName: pgo