Verify WP-CLI OpenPGP signatures before installing

[ypid]

Hi there

Now that WP-CLI provides OpenPGP signatures for releases it would be great if the wpcli role would check them.

Example: https://github.com/debops/ansible-hashicorp Current: roles/wpcli/tasks/main.yml Ref: https://github.com/wp-cli/wp-cli/issues/2121 Reason: https://github.com/jchaney/owncloud/pull/12, https://github.com/asdf-vm/asdf-nodejs/pull/25