feat(dataflow): update the API

#### dataflow:v1b3

The following keys were added:
- schemas.ParameterMetadata.properties.customMetadata.additionalProperties.type
- schemas.ParameterMetadata.properties.customMetadata.description
- schemas.ParameterMetadata.properties.customMetadata.type
- schemas.Snapshot.properties.region.description
- schemas.Snapshot.properties.region.type

discovery/dataflow-v1b3.json

@@ -2225,7 +2225,7 @@
       }
     }
   },
-  "revision": "20210408",
+  "revision": "20210420",
   "rootUrl": "https://dataflow.googleapis.com/",
   "schemas": {
     "ApproximateProgress": {
@@ -4603,6 +4603,13 @@
       "description": "Metadata for a specific parameter.",
       "id": "ParameterMetadata",
       "properties": {
+        "customMetadata": {
+          "additionalProperties": {
+            "type": "string"
+          },
+          "description": "Optional. Additional metadata for describing this parameter.",
+          "type": "object"
+        },
         "helpText": {
           "description": "Required. The help text to display for the parameter.",
           "type": "string"
@@ -5405,6 +5412,10 @@
           },
           "type": "array"
         },
+        "region": {
+          "description": "Cloud region where this snapshot lives in, e.g., \"us-central1\".",
+          "type": "string"
+        },
         "sourceJobId": {
           "description": "The job this snapshot was created from.",
           "type": "string"

src/apis/dataflow/v1b3.ts

@@ -1769,6 +1769,10 @@ export namespace dataflow_v1b3 {
    * Metadata for a specific parameter.
    */
   export interface Schema$ParameterMetadata {
+    /**
+     * Optional. Additional metadata for describing this parameter.
+     */
+    customMetadata?: {[key: string]: string} | null;
     /**
      * Required. The help text to display for the parameter.
      */
@@ -2362,6 +2366,10 @@ export namespace dataflow_v1b3 {
      * PubSub snapshot metadata.
      */
     pubsubMetadata?: Schema$PubsubSnapshotMetadata[];
+    /**
+     * Cloud region where this snapshot lives in, e.g., "us-central1".
+     */
+    region?: string | null;
     /**
      * The job this snapshot was created from.
      */
@@ -4759,6 +4767,7 @@ export namespace dataflow_v1b3 {
      *   //   "id": "my_id",
      *   //   "projectId": "my_projectId",
      *   //   "pubsubMetadata": [],
+     *   //   "region": "my_region",
      *   //   "sourceJobId": "my_sourceJobId",
      *   //   "state": "my_state",
      *   //   "ttl": "my_ttl"
@@ -7338,6 +7347,7 @@ export namespace dataflow_v1b3 {
      *   //   "id": "my_id",
      *   //   "projectId": "my_projectId",
      *   //   "pubsubMetadata": [],
+     *   //   "region": "my_region",
      *   //   "sourceJobId": "my_sourceJobId",
      *   //   "state": "my_state",
      *   //   "ttl": "my_ttl"
@@ -9267,6 +9277,7 @@ export namespace dataflow_v1b3 {
      *   //   "id": "my_id",
      *   //   "projectId": "my_projectId",
      *   //   "pubsubMetadata": [],
+     *   //   "region": "my_region",
      *   //   "sourceJobId": "my_sourceJobId",
      *   //   "state": "my_state",
      *   //   "ttl": "my_ttl"
@@ -10323,6 +10334,7 @@ export namespace dataflow_v1b3 {
      *   //   "id": "my_id",
      *   //   "projectId": "my_projectId",
      *   //   "pubsubMetadata": [],
+     *   //   "region": "my_region",
      *   //   "sourceJobId": "my_sourceJobId",
      *   //   "state": "my_state",
      *   //   "ttl": "my_ttl"