commit a5498e95d873aa5a301930871f47173fc22134ca
Author: Tom Hughes <tom@compton.nu>
Date:   Wed Oct 4 19:00:45 2017 +0100

    Update for mime 2.x

diff --git a/lib/millstone.js b/lib/millstone.js
index 01a59cf..7d35011 100644
--- a/lib/millstone.js
+++ b/lib/millstone.js
@@ -315,7 +315,7 @@ function guessExtension(headers) {
         if (headers['content-type'].indexOf('subtype=gml') != -1) {
             return '.gml'; // avoid .xml being detected for gml
         }
-        var ext_no_dot = mime.extension(headers['content-type'].split(';')[0]);
+        var ext_no_dot = mime.getExtension(headers['content-type'].split(';')[0]);
         var ext = '.'+ext_no_dot;
         if (isValidExt(ext)) {
             return ext;