Bump AWS SDK

Fixes https://github.com/docker/distribution/issues/3097

Signed-off-by: Yong Wen Chua <lawliet89@users.noreply.github.com>

vendor/github.com/aws/aws-sdk-go/private/checksum/content_md5.go

@@ -0,0 +1,53 @@
+package checksum
+
+import (
+	"crypto/md5"
+	"encoding/base64"
+	"fmt"
+
+	"github.com/aws/aws-sdk-go/aws"
+	"github.com/aws/aws-sdk-go/aws/awserr"
+	"github.com/aws/aws-sdk-go/aws/request"
+)
+
+const contentMD5Header = "Content-Md5"
+
+// AddBodyContentMD5Handler computes and sets the HTTP Content-MD5 header for requests that
+// require it.
+func AddBodyContentMD5Handler(r *request.Request) {
+	// if Content-MD5 header is already present, return
+	if v := r.HTTPRequest.Header.Get(contentMD5Header); len(v) != 0 {
+		return
+	}
+
+	// if S3DisableContentMD5Validation flag is set, return
+	if aws.BoolValue(r.Config.S3DisableContentMD5Validation) {
+		return
+	}
+
+	// if request is presigned, return
+	if r.IsPresigned() {
+		return
+	}
+
+	// if body is not seekable, return
+	if !aws.IsReaderSeekable(r.Body) {
+		if r.Config.Logger != nil {
+			r.Config.Logger.Log(fmt.Sprintf(
+				"Unable to compute Content-MD5 for unseekable body, S3.%s",
+				r.Operation.Name))
+		}
+		return
+	}
+
+	h := md5.New()
+
+	if _, err := aws.CopySeekableBody(h, r.Body); err != nil {
+		r.Error = awserr.New("ContentMD5", "failed to compute body MD5", err)
+		return
+	}
+
+	// encode the md5 checksum in base64 and set the request header.
+	v := base64.StdEncoding.EncodeToString(h.Sum(nil))
+	r.HTTPRequest.Header.Set(contentMD5Header, v)
+}