Update vendor/

vendor/github.com/emersion/go-message/charset/header.go

@@ -0,0 +1,22 @@
+package charset
+
+import (
+	"mime"
+)
+
+var wordDecoder = &mime.WordDecoder{CharsetReader: Reader}
+
+// DecodeHeader decodes an internationalized header field. If it fails, it
+// returns the input string and the error.
+func DecodeHeader(s string) (string, error) {
+	dec, err := wordDecoder.DecodeHeader(s)
+	if err != nil {
+		return s, err
+	}
+	return dec, nil
+}
+
+// EncodeHeader encodes an internationalized header field.
+func EncodeHeader(s string) string {
+	return mime.QEncoding.Encode("utf-8", s)
+}