feat: Update pack CLI to v0.12.0
Pack was previously at v0.9.0. This contains primarily fixes and new features, but v0.11.0 does come with one potentially breaking change: Builders with lifecycle versions that don't have a published lifecycle image will error (https://github.com/buildpacks/pack/pull/644/).
See the upstream release notes of each release for details:
Edited by Hordur Freyr Yngvason