List of CI checks

[savchenko]

Re. #140, what should tested as the part of CI run? So far:

1. Documentation build from .md files
2. GH-actions "matrix" Minimum supported Rust version #216 (comment) to test against minimum supported and stable Rust versions.
3. Task/Task-server compilations

Please feel free to expand further.

[djmitche]

Aside from the matrix, I think this is all tested already. We also run the full test suite (implying compilation) and a cargo audit.