Update kaniko template to support caching
relates to https://git.iwoca.co.uk/iwoca/gruntwork/infrastructure-live/-/issues/250
- Adds support for cache, cache-copy-layers and cache-repo variables.
- Moved destination to the script section, is there a use case where we don't want a destination?
- Renamed pull_args to addtional_args for clarity
Edited by Chris Cannon