Add missing poddisruption budget permissions in manager cluster role

Background
---
Open feature operator now attempts to list, create, and watch pod disruption budget resources for flagd proxy since it can now configure HA replica for flagd proxy

Changes
---
* update existing ClusterRole configuration to include poddisruptionbudget resource permissions for api group: policy

Testing
---
* manually apply changes to ClusterRole resource, change FlagSource and watch for permission errors. Retry with extra verbs until no reconcile errors were encountered.

config/rbac/role.yaml

@@ -147,3 +147,11 @@ rules:
   verbs:
   - get
   - update
+- apiGroups:
+    - policy
+  resources:
+    - poddisruptionbudgets
+  verbs:
+    - list
+    - create
+    - watch