Remove deprecated 'logtostderr' argument for kube-rbac-proxy (#2198)

Signed-off-by: Simon Pasquier <spasquie@redhat.com>

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

@@ -50,7 +50,6 @@ function(params) {
   name: krp._config.name,
   image: krp._config.image,
   args: [
-    '--logtostderr',
     '--secure-listen-address=' + krp._config.secureListenAddress,
     '--tls-cipher-suites=' + std.join(',', krp._config.tlsCipherSuites),
     '--upstream=' + krp._config.upstream,