add Apache license to build.sbt

[pjfanning]

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• I had searched in the issues and found no similar issues.

Version

n/a

Component(s)

Other

Minimal reproduce step

n/a

What did you expect to see?

license headers

What did you see instead?

missing header

Anything Else?

No response

Are you willing to submit a PR?

• I'm willing to submit a PR!