Switch to whitelisting the files shipped in the resulting gem

[ekohl]

Files included before:

.github
.github/dependabot.yml
.github/release.yml
.github/workflows
.github/workflows/gem_release.yaml
.github/workflows/prepare_release.yml
.github/workflows/release.yml
.github/workflows/unit_tests.yaml
.gitignore
.rspec
.travis.yml
CHANGELOG.md
CODEOWNERS
CODE_OF_CONDUCT.md
CONTRIBUTING.md
Gemfile
LICENSE
README.md
Rakefile
bin
bin/console
bin/setup
exe
exe/puppetserver-ca
lib
lib/puppetserver
lib/puppetserver/ca
lib/puppetserver/ca.rb
lib/puppetserver/ca/action
lib/puppetserver/ca/action/clean.rb
lib/puppetserver/ca/action/delete.rb
lib/puppetserver/ca/action/enable.rb
lib/puppetserver/ca/action/generate.rb
lib/puppetserver/ca/action/import.rb
lib/puppetserver/ca/action/list.rb
lib/puppetserver/ca/action/migrate.rb
lib/puppetserver/ca/action/prune.rb
lib/puppetserver/ca/action/revoke.rb
lib/puppetserver/ca/action/setup.rb
lib/puppetserver/ca/action/sign.rb
lib/puppetserver/ca/certificate_authority.rb
lib/puppetserver/ca/cli.rb
lib/puppetserver/ca/config
lib/puppetserver/ca/config/puppet.rb
lib/puppetserver/ca/config/puppetserver.rb
lib/puppetserver/ca/errors.rb
lib/puppetserver/ca/host.rb
lib/puppetserver/ca/local_certificate_authority.rb
lib/puppetserver/ca/logger.rb
lib/puppetserver/ca/stub.rb
lib/puppetserver/ca/utils
lib/puppetserver/ca/utils/cli_parsing.rb
lib/puppetserver/ca/utils/config.rb
lib/puppetserver/ca/utils/file_system.rb
lib/puppetserver/ca/utils/http_client.rb
lib/puppetserver/ca/utils/inventory.rb
lib/puppetserver/ca/utils/signing_digest.rb
lib/puppetserver/ca/version.rb
lib/puppetserver/ca/x509_loader.rb
openvoxserver-ca.gemspec
tasks
tasks/spec.rake
tasks/vox.rake

Files included after:

CHANGELOG.md
CODE_OF_CONDUCT.md
CONTRIBUTING.md
LICENSE
README.md
exe
exe/puppetserver-ca
lib
lib/puppetserver
lib/puppetserver/ca
lib/puppetserver/ca.rb
lib/puppetserver/ca/action
lib/puppetserver/ca/action/clean.rb
lib/puppetserver/ca/action/delete.rb
lib/puppetserver/ca/action/enable.rb
lib/puppetserver/ca/action/generate.rb
lib/puppetserver/ca/action/import.rb
lib/puppetserver/ca/action/list.rb
lib/puppetserver/ca/action/migrate.rb
lib/puppetserver/ca/action/prune.rb
lib/puppetserver/ca/action/revoke.rb
lib/puppetserver/ca/action/setup.rb
lib/puppetserver/ca/action/sign.rb
lib/puppetserver/ca/certificate_authority.rb
lib/puppetserver/ca/cli.rb
lib/puppetserver/ca/config
lib/puppetserver/ca/config/puppet.rb
lib/puppetserver/ca/config/puppetserver.rb
lib/puppetserver/ca/errors.rb
lib/puppetserver/ca/host.rb
lib/puppetserver/ca/local_certificate_authority.rb
lib/puppetserver/ca/logger.rb
lib/puppetserver/ca/stub.rb
lib/puppetserver/ca/utils
lib/puppetserver/ca/utils/cli_parsing.rb
lib/puppetserver/ca/utils/config.rb
lib/puppetserver/ca/utils/file_system.rb
lib/puppetserver/ca/utils/http_client.rb
lib/puppetserver/ca/utils/inventory.rb
lib/puppetserver/ca/utils/signing_digest.rb
lib/puppetserver/ca/version.rb
lib/puppetserver/ca/x509_loader.rb