Pull in the latest version of the cisagov/guacscanner Docker image

[jsf9k]

🗣 Description

This pull request modifies the Ansible role to pull in the latest version of the cisagov/guacscanner Docker image.

💭 Motivation and context

This role is applied to AMIs that run on EC2 instances that do not have internet access, so we need to pull down the same version of the Docker image that is used in cisagov/guacamole-composition.

🧪 Testing

All pre-commit hooks and molecule tests pass.

✅ Pre-approval checklist

• [x] This PR has an informative and human-readable title.
• [x] Changes are limited to a single goal - eschew scope creep!
• [x] All relevant type-of-change labels have been added.
• [x] I have read the CONTRIBUTING document.
• [x] These code changes follow cisagov code standards.
• [x] Tests have been added and/or modified to cover the changes in this PR.
• [ ] All new and existing tests pass.

[jsf9k]

The Kali-based molecule testing will fail until cisagov/skeleton-ansible-role#92 is merged into this repository. I'll rebase this branch and re-run the GitHub Actions once that happens.