Corrected SMTP-UTF8 fields

cabal.project

@@ -0,0 +1 @@
+packages: ../*/*.cabal

src/Walrus/Backend/Metadata.hs

@@ -228,7 +228,7 @@ renderMetadata m = BS.concat $ serializeDt ++ serializeMain ++ ["\r\n"]
         "Client-Name: ", s cnm, "\r\n",
         "Return-Path: ", s . normalize $ rfm, "\r\n",
         "Body-Encoding: ", show enc, "\r\n",
-        "Data.SMTP.UTF8: ", serialBool utf, "\r\n"
+        "SMTP-UTF8: ", serialBool utf, "\r\n"
         ] :: [String]
       in map s h ++ toStr ++ failStr
     serializeHandle (HandleAddress a) = ["To: ", renderMetadataAddress a, "\r\n"]
@@ -304,7 +304,7 @@ parseMetadata = do
         enc <- hdr "Body-Encoding" Mime.parseBodyEncoding
         return $ \(m, ip, p) -> (set mbodyEnc enc m, ip, p),
       do
-         utf <- hdr "Data.SMTP.UTF8" parseMetadataBool
+         utf <- hdr "SMTP-UTF8" parseMetadataBool
          return $ \(m, ip, p) -> (set msmtpUtf8 utf m, ip, p),
       do
         usr <- hdr "Auth-User" A.takeByteString