Update dependencies

Among others, this updates minio-go, so that the new "eu-west-3" zone
for AWS is supported.

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

@@ -150,8 +150,9 @@ There are two ways to construct schemas with this package.
 You can build a schema by hand, like so:
 
     schema1 := bigquery.Schema{
-        &bigquery.FieldSchema{Name: "Name", Required: true, Type: bigquery.StringFieldType},
-        &bigquery.FieldSchema{Name: "Grades", Repeated: true, Type: bigquery.IntegerFieldType},
+        {Name: "Name", Required: true, Type: bigquery.StringFieldType},
+        {Name: "Grades", Repeated: true, Type: bigquery.IntegerFieldType},
+        {Name: "Optional", Required: false, Type: bigquery.IntegerFieldType},
     }
 
 Or you can infer the schema from a struct:
@@ -159,6 +160,7 @@ Or you can infer the schema from a struct:
     type student struct {
         Name   string
         Grades []int
+        Optional bigquery.NullInt64
     }
     schema2, err := bigquery.InferSchema(student{})
     if err != nil {
@@ -166,19 +168,24 @@ Or you can infer the schema from a struct:
     }
     // schema1 and schema2 are identical.
 
-Struct inference supports tags like those of the encoding/json package,
-so you can change names or ignore fields:
+Struct inference supports tags like those of the encoding/json package, so you can
+change names, ignore fields, or mark a field as nullable (non-required). Fields
+declared as on of the Null types (NullInt64, NullFloat64, NullString, NullBool,
+NullTimestamp, NullDate, NullTime and NullDateTime) are automatically inferred as
+nullable, so the "nullable" tag is only needed for []byte and pointer-to-struct
+fields.
 
     type student2 struct {
-        Name   string `bigquery:"full_name"`
-        Grades []int
-        Secret string `bigquery:"-"`
+        Name     string `bigquery:"full_name"`
+        Grades   []int
+        Secret   string `bigquery:"-"`
+        Optional []byte `bigquery:",nullable"
     }
     schema3, err := bigquery.InferSchema(student2{})
     if err != nil {
         // TODO: Handle error.
     }
-    // schema3 has fields "full_name" and "Grade".
+    // schema3 has required fields "full_name" and "Grade", and nullable BYTES field "Optional".
 
 Having constructed a schema, you can create a table with it like so: