I had noticed quite a number of casks that still have `license :unknown`
along with the generated placeholder message. I thought I would take
some spare time to update a few of the casks where I could find
relevant information. I've stuck with the guidance on the license
stanzas section of the Cask Language Reference. Where there was doubt,
I simply didn't update.
I'm happy to continue updating these from time to time, if you're
happy to receive them.