"./launch_here.rb:17:in <main>': undefined method exists?' for File:Class (NoMethodError)..."

[antdude]

Unable to launch rbot after upgrading Fedora to v39 with rbot (even tried with https://github.com/ruby-rbot/rbot/archive/master.zip and "git clone https://github.com/ruby-rbot/rbot.git"):

$ /usr/bin/ruby-mri ./launch_here.rb
Running from /home/ant/Downloads/rbot-master
./launch_here.rb:17:in <main>': undefined method exists?' for File:Class (NoMethodError)

if File.exists? '.git'
^^^^^^^^
Did you mean? exist?

$ /usr/bin/ruby-mri --version
ruby 3.2.2 (2023-03-30 revision e51014f9c0) [x86_64-linux]