Bump rack from 3.1.20 to 3.1.21 in /code-samples/serving/hello-world/helloworld-ruby#6612

knative-prow[bot] merged 1 commit intomainknative/docs:mainfrom

dependabot/bundler/code-samples/serving/hello-world/helloworld-ruby/rack-3.1.21knative/docs:dependabot/bundler/code-samples/serving/hello-world/helloworld-ruby/rack-3.1.21Copy head branch name to clipboard