Add build.resources to workload

[waciumawanjohi]

Description of problem

A supply chain may want to include a template of a build step. Such a step may require a specifications of resources to allocate to the build process. See for example kpack image use of k8s resource limits/requests (corev1.ResourceRequirements).

Proposed solution

The workload currently has a spec.build.env field. Add a spec.build.resources field.

[waciumawanjohi]

This proposal is under discussion by the team.

[squeedee]

I am concerned that the workload first class fields becomes a big ball of mud. Already it's not obvious which fields are required in combination with others, and resources, like env, might not always work with a build step.

My preference is something self describing, which is a list of params exposed to the workload by the supply chain, with docs, and in time, with a deterministic, statically analysable contract, eg: I provide a workload with a certain label, and the supply chain can immediately tell me "you forgot params.resources"