Resolve diffy gem issues for 3.2.2

The diffy gem has a number of issues when using ruby 3.2.2:

55 examples, 16 failures

rspec ./spec/diffy_spec.rb:489 # Diffy::Diff#to_s html should treat unix vs windows newlines as differences
rspec ./spec/diffy_spec.rb:439 # Diffy::Diff#to_s html should escape html
rspec ./spec/diffy_spec.rb:283 # Diffy::Diff#to_s with one line different should accept a default options
rspec ./spec/diffy_spec.rb:291 # Diffy::Diff#to_s with one line different should show one line added
rspec ./spec/diffy_spec.rb:262 # Diffy::Diff#to_s with one line different should show one line removed
rspec ./spec/diffy_spec.rb:270 # Diffy::Diff#to_s with one line different to_s should accept a format key
rspec ./spec/diffy_spec.rb:275 # Diffy::Diff#to_s with one line different should accept a default format option
rspec ./spec/diffy_spec.rb:131 # Diffy::Diff options[:context] should limit context lines to 1
rspec ./spec/diffy_spec.rb:154 # Diffy::Diff options[:include_plus_and_minus_in_html] formats includes symbols in html_simple
rspec ./spec/diffy_spec.rb:168 # Diffy::Diff options[:include_plus_and_minus_in_html] formats includes symbols in html
rspec ./spec/diffy_spec.rb:188 # Diffy::Diff options[:include_diff_info] defaults to false
rspec ./spec/diffy_spec.rb:213 # Diffy::Diff options[:include_diff_info] formats works for :html_simple
rspec ./spec/diffy_spec.rb:663 # Diffy::SplitDiff#right should only highlight insertions
rspec ./spec/diffy_spec.rb:673 # Diffy::SplitDiff#right should also format right diff as html
rspec ./spec/diffy_spec.rb:646 # Diffy::SplitDiff#left should also format left diff as html
rspec ./spec/diffy_spec.rb:635 # Diffy::SplitDiff#left should only highlight deletions

The gem doesn't look to be maintained at the moment and the travisCI builds are missing: https://app.travis-ci.com/samg/diffy

Availability and Testing

Regression testing, please ensure associated MR is labelled with pipeline:run-all-e2e and e2e:package-and-test job is passing.