refactor: required changes from api build types migration

[plyr4]

need this to let the worker build in https://github.com/go-vela/worker/pull/608

this is subject to change when pipeline and step are migrated, but until then we need it to build the worker

cd go-vela/worker

make build

executor/local/step.go:53:50: c.build.ToLibrary undefined (type *"github.com/go-vela/server/api/types".Build has no field or method ToLibrary)