fix(firebaserules): update the API

#### firebaserules:v1

The following keys were changed:
- schemas.Empty.description

discovery/firebaserules-v1.json

@@ -477,7 +477,7 @@
       }
     }
   },
-  "revision": "20220127",
+  "revision": "20220323",
   "rootUrl": "https://firebaserules.googleapis.com/",
   "schemas": {
     "Arg": {
@@ -496,7 +496,7 @@
       "type": "object"
     },
     "Empty": {
-      "description": "A generic empty message that you can re-use to avoid defining duplicated empty messages in your APIs. A typical example is to use it as the request or the response type of an API method. For instance: service Foo { rpc Bar(google.protobuf.Empty) returns (google.protobuf.Empty); } The JSON representation for `Empty` is empty JSON object `{}`.",
+      "description": "A generic empty message that you can re-use to avoid defining duplicated empty messages in your APIs. A typical example is to use it as the request or the response type of an API method. For instance: service Foo { rpc Bar(google.protobuf.Empty) returns (google.protobuf.Empty); }",
       "id": "Empty",
       "properties": {},
       "type": "object"

src/apis/firebaserules/v1.ts

@@ -139,7 +139,7 @@ export namespace firebaserules_v1 {
     exactValue?: any | null;
   }
   /**
-   * A generic empty message that you can re-use to avoid defining duplicated empty messages in your APIs. A typical example is to use it as the request or the response type of an API method. For instance: service Foo { rpc Bar(google.protobuf.Empty) returns (google.protobuf.Empty); \} The JSON representation for `Empty` is empty JSON object `{\}`.
+   * A generic empty message that you can re-use to avoid defining duplicated empty messages in your APIs. A typical example is to use it as the request or the response type of an API method. For instance: service Foo { rpc Bar(google.protobuf.Empty) returns (google.protobuf.Empty); \}
    */
   export interface Schema$Empty {}
   /**