docs(README): bump version to 0.8.7

[Chaitanya-Keyal]

Description

Bumped all version references in the README to 0.8.7!

Additional Information

• To be merged after the release is signed and tagged.

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This pull request is categorized as a:

• Documentation

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Checklist

I ran pytest locally

• N/A

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I included screenshots of any new or modified screens

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I added or updated tests

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I tested this PR hands-on on the following platform(s):

• N/A

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I have reviewed these notes:

• Keep your changes limited in scope.
• If you uncover other issues or improvements along the way, ideally submit those as a separate PR.
• The more complicated the PR, the harder it is to review, test, and merge.
• We appreciate your efforts, but we're a small team of volunteers so PR review can be a very slow process.
• Please only "@" mention a contributor if their input is truly needed to enable further progress.

• I understand

[kdmukai]

ACK.

Can be merged just before / just after(?) the v0.8.7 release is finalized.