Add .ico mimetype to utility, a-chris

diff --git a/src/library/Utility.php b/src/library/Utility.php
index 657239ccf..bfb21dc02 100755
--- a/src/library/Utility.php
+++ b/src/library/Utility.php
@@ -1857,6 +1857,7 @@ function mimeType($file_name)
         $mime_types = [
             ".avi" => "video/x-msvideo",
             ".bmp" => "image/bmp",
+            ".ico" => "image/x-icon",
             ".css" => "text/css",
             ".gif" => "image/gif",
             ".jpg" => "image/jpeg",