Document instructions for validating locally

[mr-c]

Here is what I had to do:

sudo gem install install_specific
gem install_specific --user-install https://github.com/citation-file-format/ruby-cff.git

and then make a local file test.rb

require 'cff'
begin
  CFF::File.validate!('CITATION.cff')
end

ruby test.rb

[arfon]

Perhaps this could be manifested as some kind of basic GitHub Action that essentially runs these steps whenever the code is updated?

[hainesr]

Ooh, a GitHub action to validate CFF files would be ace.

[sdruskat]

https://github.com/marketplace/actions/cffconvert has done this for 1.1.0 and older, and will be updated at some point to support 1.2.0. It's a bit clunky atm, and multi-purpose (also used for conversion).