* Validate removal versions.
* Validate that removal collection versions and version_added collection versions conform to semver spec.
* Validate removal version numbers in meta/runtime.yml.
* Stricter validation for isodates (f.ex. YYYY-M-D is not allowed).
* Improve error reporting.
* Validate removal collection versions.
Co-authored-by: Andrew Klychkov <aaklychkov@mail.ru>
