Github Actions support

[sgammon]

⚠️ Is your feature request related to a problem? Please describe

It would be very cool to add better Github Actions integration, so that we could accomplish the following:

• Build stats/metrics
• Dependency tree diff stats
• Key file diff stats / risk stats

💡 Describe the solution you'd like

The plugin needs reporting architecture before this is possible, but running it under the context of a Github Action should trigger special behavior which:

• Produces summaries of above
• Halts builds (if desired) based on failures of above

🤚 Do you want to develop this feature yourself?

• Yes
• No

[sgammon]

blocked on #77