Add the license to pbt

[tenzen-y]

Signed-off-by: tenzen-y yuki.iwai.tz@gmail.com

What this PR does / why we need it:
I added the license to PBT.

Which issue(s) this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when PR gets merged):
Fixes #

Checklist:

• Docs included if any changes are user facing

[coveralls]

Coverage decreased (-0.1%) to 73.431% when pulling 886058b on tenzen-y:update-boilerplate into e02eb6e on kubeflow:master.

[tenzen-y]

@kubeflow/wg-automl-leads PTAL.

[gaocegege]

/lgtm
/approve

[google-oss-prow]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: gaocegege, tenzen-y

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[a9p]

Hey @tenzen-y & @gaocegege! I originally excluded the KF copyright on this file since it is heavily based on / copied from the Ray implementation here. I defer to your expertise, but wanted to surface this point in the event it necessitates changing anything!

[tenzen-y]

Hey @tenzen-y & @gaocegege! I originally excluded the KF copyright on this file since it is heavily based on / copied from the Ray implementation here. I defer to your expertise, but wanted to surface this point in the event it necessitates changing anything!

@a9p Thanks for your response!
We have created other trial images based on other codes, same as the simple-pbt, and added the KF copyright to all trial images.
So we need to add the KF copyright to the simple-pbt.

Although, we might be able to add readme, same as other trial images such as the tf-mnit-with-summaries since it would be good to clarify that the simple-pbt is heavily based on from Ray.

WDYT?