Document migration from BuildTemplate+Build to Task+TaskRun

[imjasonh]

Related to #147

As a former Build user, it should be straightforward for me to migrate BuildTemplates and Builds I had previously defined to match the new model for Pipelines.

In the new model, a BuildTemplate is roughly equivalent to a Task (stateless, parameterized resources which are invoked), and a Build is roughly equivalent to a TaskRun (the running invocation, with state).

There are some differences, particularly around how Task parameters are defined and passed into steps, and how currently you can only create a Task from a pre-defined TaskRun (#249).

At a minimum we should document how to migrate to the new world, and ideally we would be able to write a script that transforms a Build YAML into a TaskRun YAML, likewise for BuildTemplate -> Task.

[bobcatfish]

I think this is unblocked now! But @shashwathi I'm guessing you're in a good position to take this on since you've migrated so many examples in #493 🙏 ? No worries tho if you'd rather not take it on :D

[shashwathi]

/assign @shashwathi

[vdemeester]

I think we are good closing this one, https://github.com/tektoncd/pipeline/blob/master/docs/migrating-from-knative-build.md is there, and knative/build is "long gone" 👼

/close

[tekton-robot]

@vdemeester: Closing this issue.

In response to this:

I think we are good closing this one, https://github.com/tektoncd/pipeline/blob/master/docs/migrating-from-knative-build.md is there, and knative/build is "long gone" 👼

/close

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