Skipping run phases

We've just released a subtle update allowing skipping certain run phases by setting environment variables:

• SPACELIFT_SKIP_APPLYING works for all supported IaC platforms, and will make the APPLYING phase of any run a no-op;
• SPACELIFT_SKIP_DESTROYING will make the DESTROYING phase of Terraform module tests a no-op;

This new mechanism can be used to create plan-only stacks, and plan-only module test cases, as well as enable multiple other, more complex scenarios. If you end up using it to build something awesome, please make sure to let us know!