Fixing already deprecated apiVersion for Role and RoleBinding of k8s manifests

[Underforest]

Hi folks,

Now we use deprecated apiVersion ( "rbac.authorization.k8s.io/v1beta1" ) for Role and RoleBinding in Prometheus manifests
The current version of apiVersion is "rbac.authorization.k8s.io/v1".
Please fix it.

P.S.: I tried to create PR but your policy has dined my try.