Release v4.0.2

Changelog:

• Fix the build of gtktsm with recent versions of pango
• Move to GitHub Actions from TravisCI

Release v4.0.1

Changelog:

• Port from autotools to CMake build system
• Arbitrary color palette configurable via API
• More unit tests
• Release tag name changes from libtsm-x.y.z to vx.y.z
• Bug fixes