vendor: update buildkit to master@31c870e82a48

Signed-off-by: Justin Chadwell <me@jedevc.com>

vendor/github.com/aws/smithy-go/encoding/json/array.go

@@ -0,0 +1,35 @@
+package json
+
+import (
+	"bytes"
+)
+
+// Array represents the encoding of a JSON Array
+type Array struct {
+	w          *bytes.Buffer
+	writeComma bool
+	scratch    *[]byte
+}
+
+func newArray(w *bytes.Buffer, scratch *[]byte) *Array {
+	w.WriteRune(leftBracket)
+	return &Array{w: w, scratch: scratch}
+}
+
+// Value adds a new element to the JSON Array.
+// Returns a Value type that is used to encode
+// the array element.
+func (a *Array) Value() Value {
+	if a.writeComma {
+		a.w.WriteRune(comma)
+	} else {
+		a.writeComma = true
+	}
+
+	return newValue(a.w, a.scratch)
+}
+
+// Close encodes the end of the JSON Array
+func (a *Array) Close() {
+	a.w.WriteRune(rightBracket)
+}