Update Transmit cask to v4.4.1 from v4.4.0

This patch updates the version of Transmit to version 4.4.1 from the
current version of 4.4.0. It includes a new checksum, version, and URL.

Audit:
```sh
❯ brew cask audit transmit
audit for transmit: passed
```

Casks/transmit.rb

@@ -1,7 +1,7 @@
 class Transmit < Cask
-  url 'http://www.panic.com/transmit/d/Transmit%204.4.zip'
+  url 'http://www.panic.com/transmit/d/Transmit%204.4.1.zip'
   homepage 'http://panic.com/transmit'
-  version '4.4'
+  version '4.4.1'
-  sha1 'fe4c41ce2945f79ed5b613dc51aea4112bd051f3'
+  sha1 '8878d15c0cb8913159a30f70da45bbf4fa9ee6c5'
 	link 'Transmit.app'
 end