feat(userAgent): allow for optional user agent to be provided (#671)

* feat(userAgent): allow for optional user agent to be provided

* chore: linted

* updates @google-cloud/common version

Author: steffnay

package.json

@@ -48,7 +48,7 @@
     "precompile": "gts clean"
   },
   "dependencies": {
-    "@google-cloud/common": "^3.0.0",
+    "@google-cloud/common": "^3.1.0",
     "@google-cloud/paginator": "^3.0.0",
     "@google-cloud/promisify": "^2.0.0",
     "arrify": "^2.0.1",

src/bigquery.ts

@@ -163,6 +163,7 @@ export interface BigQueryOptions extends common.GoogleAuthOptions {
   autoRetry?: boolean;
   maxRetries?: number;
   location?: string;
+  userAgent?: string;
   /**
    * The API endpoint of the service used to make requests.
    * Defaults to `bigquery.googleapis.com`.
@@ -199,6 +200,8 @@ export interface BigQueryOptions extends common.GoogleAuthOptions {
  *     native Promises.
  * @property {string} [location] The geographic location of all datasets and
  *     jobs referenced and created through the client.
+ * @property {string} [userAgent] The value to be prepended to the User-Agent
+ *     header in API requests.
  * @property {string[]} [scopes] Additional OAuth scopes to use in requests. For
  *     example, to access an external data source, you may need the
  *     `https://www.googleapis.com/auth/drive.readonly` scope.