fix(datamigration): update the API

#### datamigration:v1beta1

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

#### datamigration:v1

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

discovery/datamigration-v1.json

@@ -1049,7 +1049,7 @@
       }
     }
   },
-  "revision": "20220216",
+  "revision": "20220321",
   "rootUrl": "https://datamigration.googleapis.com/",
   "schemas": {
     "AuditConfig": {
@@ -1436,7 +1436,7 @@
       "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"

discovery/datamigration-v1beta1.json

@@ -1049,7 +1049,7 @@
       }
     }
   },
-  "revision": "20211201",
+  "revision": "20220321",
   "rootUrl": "https://datamigration.googleapis.com/",
   "schemas": {
     "AuditConfig": {
@@ -1377,7 +1377,7 @@
       "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/datamigration/v1.ts

@@ -347,7 +347,7 @@ export namespace datamigration_v1 {
     dumpFlags?: Schema$DumpFlag[];
   }
   /**
-   * A generic empty message that you can re-use to avoid defining duplicated empty messages in your APIs. A typical example is to use it as the request or the response type of an API method. For instance: service Foo { rpc Bar(google.protobuf.Empty) returns (google.protobuf.Empty); \} The JSON representation for `Empty` is empty JSON object `{\}`.
+   * A generic empty message that you can re-use to avoid defining duplicated empty messages in your APIs. A typical example is to use it as the request or the response type of an API method. For instance: service Foo { rpc Bar(google.protobuf.Empty) returns (google.protobuf.Empty); \}
    */
   export interface Schema$Empty {}
   /**

src/apis/datamigration/v1beta1.ts

@@ -313,7 +313,7 @@ export namespace datamigration_v1beta1 {
     provider?: string | 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 {}
   /**