Add bundler 2.2.5, remove bundler 2.2.4
Add bundler 2.2.5, remove bundler 2.2.4

for stack(s) cflinuxfs3 [#176449223]

cloudfoundry/ruby-buildpack,cloudfoundry/ruby-buildpack,cloudfoundry/ruby-buildpack,cloudfoundry/ruby-buildpack,cloudfoundry/ruby-buildpack