Gemfile doesn't read ruby version

[Martin]

While trying to set up a new rails app using this awesome template I encountered the following error:

[!] There was an error parsing `Gemfile`: Illformed requirement ["3.1.1"]. Bundler cannot continue.

 #  from /Users/martin/git/j4s-monolith/Gemfile:4
 #  -------------------------------------------
 #
 >  ruby 'File.read("./.ruby-version").strip'
 #
 #  -------------------------------------------

Using: MacOS, zsh, rvm, Ruby 3.1.1, Rails 7.0.4