Include license and notice files in published crates

[ankane]

Which issue does this PR close?

None

What changes are included in this PR?

This symlinks the LICENSE and NOTICE files so they're included in the published crates (similar to apache/arrow-rs#6767).

Are these changes tested?

N/A

[liurenjie1024]

hi, @ankane could you help to explain what's the result of this pr? I see we already have license info at at docs.rs

[ankane]

Hi @liurenjie1024, this will add the files to the crate source. The Apache 2.0 license mentions including both files with copies of the software, and it's nice for tooling like cargo vendor (microsoft/windows-rs#1587 (comment)).