Updates reason phrase for 425 response status code

The IANA HTTP status codes list was updated on 2018-07-02 to reflect a
new IETF draft, draft-ietf-httpbis-replay-04, which details a header
that may be used to indicate that an "early data" request may not yet be
accepted, as no TLS handshake has been previously made, and that the
request myust be retried after receiving the 425 response.

Author: weierophinney

src/Response.php

@@ -87,7 +87,7 @@ class Response implements ResponseInterface
         422 => 'Unprocessable Entity',
         423 => 'Locked',
         424 => 'Failed Dependency',
-        425 => 'Unordered Collection',
+        425 => 'Too Early',
         426 => 'Upgrade Required',
         428 => 'Precondition Required',
         429 => 'Too Many Requests',