Allow the path to a project.toml be configured

[matthewmcnew]

#690 adds support from project.toml but, will only find a project.toml in the root of supplied source with the name project.toml. While this behavior matches the default behavior of pack, pack also provides the a pack build --descriptor flag which allows users to set the path to a project descriptor. To enable the same behavior in kpack the image and build type should support providing the path to the descriptor in the spec.build.

Adding this functionality, naturally makes sense as an api addition to the new api being introduced in the 0.4.0 release.

[matthewmcnew]

CC' @genevieve. I heard you might have a unique usecase here?

[jromero]

@matthewmcnew is there an RFC (or otherwise high-level view) of changes incorporated in API 0.4.0? Or is it more that it's to signify that "it's ok to break compatibility"?

[matthewmcnew]

@jromero We plan on releasing a new api version alongside the existing v1alpha1 in 0.4. So, this new api version is an opportunity to include any/all breaking changes we would like to incorporate into kpack. At this time we have tagged everything 0.4 that we would like to include.

[sambhav]

Fixed in #800. Can be closed.