* Add the `kernels check` subcommand
This subcommand checks a given kernel. Currently it applies the same ABI
checks as `kernel-abi-check` in `kernel-builder`.
* Print an error when `build` contains files
* Forgot to update has_issues in two places
* Add `generate-readme` subcommand for generating a README
This README includes all the top-level functions with docs (if
docstrings are available).
* CI: attempt README generation
* Add PyYAML dependencies
* Typing fixes