Update to latest version of Chirpy theme

[neilboyd]

Currently using version 6.2.3 of Chirpy theme and Chirpy starter .
Versions later than that depend on Ruby 3.0 which I don't have on my WSL Ubuntu and I couldn't immediately figure out how to install it.
It also fails on Netlify. See also #3.
A bit of Googling shows that Netlify doesn't yet support Ruby 3.

A bit more Googling shows that maybe it is:
https://docs.netlify.com/configure-builds/manage-dependencies/#ruby

git clone https://github.com/rbenv/ruby-build.git "$(rbenv root)"/plugins/ruby-build
git -C "$(rbenv root)"/plugins/ruby-build pull
rbenv install --list
rbenv install 3.1.4
rbenv local 3.1.4
gem install bundler
bundle

If this issue is fixed then I can delete my copy of default layout. Or not - I also change the language in the html tag at the top.