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
```
`md5`, `sha1`, `sha256` all take a hexdigest string, e.g:
sha1 'f645e9da45a621415a07a7492c45923b1a1fd4d4'
`no_checksum` takes no argument, and indicates there is no checksum
for this cask. This is *not recommended*, and should only be used for
casks that have no versioned downloads.
`brew cask install` will complain if there is no sum provided (unless
`no_checksum` has been invoked), or if the sums do not match. It will
provide the computed checksum so the cask can be easily amended.
Adapted from @passcod's work in 82cc199ae6
Roderik van der Veer