Currently, Trivy traverses all paths and looks for all Gemfile.lock in a container image. However, the image sometimes has only Gemfile.lock and doesn't install gems listed in the Gemfile.lock. I think a gem should have *.gemspec file if it is installed. e.g. rake.gemspec has the information about rake.

To avoid false positives from Gemfile.lock, we are probably able to take advantage of `*