authz: fix RBAC filter config PB docs (#3895)
authz: fix RBAC filter config PB docs (#3895)

Fix the description of an `RBAC` Protobuf message example, so that it
matches the changes made to the YAML code block in PR #3477.

Risk Level: Low
Testing: N/A
Docs Changes: N/A
Release Notes: N/A

Signed-off-by: Tal Nordan <53c32b2504035e382fe651b87a0e2b4e645f3f0a@solo.io>
jrajahalme/envoy,envoyproxy/envoy,lizan/envoy,eklitzke/envoy,dnoe/envoy,jrajahalme/envoy,envoyproxy/envoy,dnoe/envoy,istio/envoy,envoyproxy/envoy-wasm,eklitzke/envoy,dnoe/envoy,jrajahalme/envoy,envoyproxy/envoy-wasm,lizan/envoy,envoyproxy/envoy,dnoe/envoy,jrajahalme/envoy,jrajahalme/envoy,lyft/envoy,istio/envoy,envoyproxy/envoy-wasm,envoyproxy/envoy,dnoe/envoy,lyft/envoy,envoyproxy/envoy,lyft/envoy,envoyproxy/envoy,eklitzke/envoy,lizan/envoy,lyft/envoy,lizan/envoy,envoyproxy/envoy-wasm,istio/envoy,eklitzke/envoy,envoyproxy/envoy,eklitzke/envoy,istio/envoy,envoyproxy/envoy-wasm,istio/envoy,eklitzke/envoy,istio/envoy,istio/envoy,envoyproxy/envoy,envoyproxy/envoy-wasm,lyft/envoy,envoyproxy/envoy,envoyproxy/envoy-wasm,jrajahalme/envoy,envoyproxy/envoy,lizan/envoy,envoyproxy/envoy,lizan/envoy,envoyproxy/envoy,lyft/envoy