Docker build fails due to expired GPG key for puppet6-release

[scale03]

Describe the Bug

The Dockerfile for the puppet_6_node service attempts to use the Puppet 6 APT repository for Ubuntu Bionic. The GPG signing key for this repository has expired, which causes the apt-get update step within the Docker build to fail. This prevents the developer test environment from being built.

Expected Behavior

The docker compose -f spec/docker-compose.yml up -d command should complete successfully, building all required test containers without error.

Steps to Reproduce

1. Clone the Bolt repository.

2. Set up a local development environment with Docker.

3. From the root of the repository, run docker compose -f spec/docker-compose.yml up -d.

Suggested Fix

The Dockerfile responsible for building the puppet_6_node container needs to be updated to import the new, valid GPG key for the Puppet APT repositories before running apt-get update.

A potential solution would involve adding a step to download and install the new public key. For example

Additional Context

The build fails with the following definitive error message:

W: GPG error: http://apt.puppetlabs.com bionic InRelease: The following signatures were invalid: EXPKEYSIG 4528B6CD9E61EF26 Puppet, Inc. Release Key (Puppet, Inc. Release Key) release@puppet.com
E: The repository 'http://apt.puppetlabs.com bionic InRelease' is not signed.