• Update base Docker image from Ubuntu 20.04 to 22.04
• Add -fcommon to CFLAGS in code and documentation (see https://github.com/perseids-tools/morpheus/releases/tag/v1.0.4)

• Update Docker from Ubuntu 18.04 to 20.04
• Update Ruby (used for tests) from 2.7 to 3.0
• Add a Docker build and Docker Hub publication action to GitHub Actions

• Add code of conduct
• Add sponsor link
• Update README
• Replace Travis with GitHub Actions

Initial release