Add bundler 2.2.16, remove bundler 2.2.15
Add bundler 2.2.16, remove bundler 2.2.15

for stack(s) cflinuxfs3 [#177697234]

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