Fix CI and upgrade test matrix

[bhuntpenn]

• Broke it down into the list of most relevant versions in 2022
• Specify the ubuntu version - 'latest' is mutable, at least the tests will work now until it's deprecated.
• Testing on OSX - the ERLEF doesn't support it, only windows and Linux
• Testing on Windows - can't see the point, no native code in Poison implementation.
• Use the latest patch versions of Elixir/Erlang - it's a best practice not to use the alpha 1.14.0 versions anyway.
• Love this project, thanks, it's so much easier to use and better for rapid integration than Jason IMHO x