Ruby 3.3 deprecation warnings: base64, bigdecimal will no longer be part of the default gems

liquid-5.4.0/lib/liquid/standardfilters.rb:4: warning: base64 was loaded from the standard library, but will no longer be part of the default gems since Ruby 3.4.0. Add base64 to your Gemfile or gemspec.

/liquid-5.4.0/lib/liquid/standardfilters.rb:5: warning: bigdecimal was loaded from the standard library, but will no longer be part of the default gems since Ruby 3.4.0. Add bigdecimal to your Gemfile or gemspec.

Since liquid does not have any dependencies in gemspec I don't feel like adding

if Gem::Version.new(RUBY_VERSION) >= Gem::Version.new('3.3')
  s.add_dependency('base64')
  s.add_dependency('bigdecimal')
end

so just leave this as issue, not PR