Bumped version to v2.19.6.
pin GitHub Actions to commit SHA (#10230)
Bumped version to v2.20.0. (#10244)
Bumped version to v2.20.0-rc.2. (#10234)
Bumped sierra version to 1.9.3.
Bumped version to v2.20.0-rc.1. SIERRA_UPDATE_NO_CHANGE_TAG=toml only.
(refactor): casm contract class