vendor: update all dependencies

vendor/cloud.google.com/go/bigquery/doc.go

@@ -20,6 +20,9 @@ Note: This package is in beta.  Some backwards-incompatible changes may occur.
 The following assumes a basic familiarity with BigQuery concepts.
 See https://cloud.google.com/bigquery/docs.
 
+See https://godoc.org/cloud.google.com/go for authentication, timeouts,
+connection pooling and similar aspects of this package.
+
 
 Creating a Client
 
@@ -294,10 +297,5 @@ Extractor, then optionally configure it, and lastly call its Run method.
     extractor.DisableHeader = true
     job, err = extractor.Run(ctx)
     // Poll the job for completion if desired, as above.
-
-Authentication
-
-See examples of authorization and authentication at
-https://godoc.org/cloud.google.com/go#pkg-examples.
 */
 package bigquery // import "cloud.google.com/go/bigquery"