docker-RTGtools v3.12.1

What's Changed

• Update make by @jsahrmann in #6
• Add default user and image source to Dockerfile by @jsahrmann in #9
• Update for v3.12.1 release by @jsahrmann in #10

New Contributors

• @jsahrmann made their first contribution in #6

Full Changelog: v3.12...v3.12.1