Explicitly declare allowPrivilegeEscalation to false

Although containers that do not run as privileged already have this set to false by kubernetes
Kubespace [asks us](https://hub.armo.cloud/docs/c-0016) to explicitly declare it to false where not needed.

Signed-off-by: Arthur Silva Sens <arthursens2005@gmail.com>

jsonnet/kube-prometheus/components/kube-rbac-proxy.libsonnet

@@ -61,5 +61,6 @@ function(params) {
     runAsUser: 65532,
     runAsGroup: 65532,
     runAsNonRoot: true,
+    allowPrivilegeEscalation: false,
   },
 }