Merge pull request #86 from Copilot-Language/T85-release-4.4

Require building with Copilot 4.4. Refs #85.

Merge pull request #83 from Copilot-Language/T82-release-4.3

Require building with Copilot 4.3. Refs #82.

Merge pull request #77 from Copilot-Language/T76-copilot-verifier-4.2

Require building with Copilot 4.2. Refs #76.

Merge pull request #73 from Copilot-Language/T72-copilot-verifier-4.1

Require building with Copilot 4.1. Refs #72.

Document changes in the CHANGELOG. Refs #69.

Document changes in CHANGELOG. Refs #58.

Merge pull request #54 from Copilot-Language/T53

Release 3.19. Refs #53.

Bump release version to 0.1