Compatibility with Ruby 3.2: File.exists? replaced with File.exist?

[damienmckenna]

With Ruby 3.3.0 I run into this error:

/usr/local/lib/ruby/gems/3.3.0/gems/gitjour-6.6.0/lib/gitjour.rb:97:in `serve': undefined method `exists?' for class File (NoMethodError)

        if File.exists?("#{path}/.git")
               ^^^^^^^^
Did you mean?  exist?
	from /usr/local/lib/ruby/gems/3.3.0/gems/gitjour-6.6.0/lib/gitjour.rb:24:in `run'
	from /usr/local/lib/ruby/gems/3.3.0/gems/gitjour-6.6.0/bin/gitjour:9:in `<top (required)>'
	from /usr/local/bin/gitjour:25:in `load'
	from /usr/local/bin/gitjour:25:in `<main>'

This is because File.exists? was replaced with File.exist? in 3.2.0: https://rubyreferences.github.io/rubychanges/3.2.html