Update llama3.md, fix typo

[mimbres]

fix typo again

What does this PR do?

Fixes # (issue)

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• This PR fixes a typo or improves the docs (you can dismiss the other checks if that's the case).
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• Did you make sure to update the documentation with your changes? Here are the
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• Did you write any new necessary tests?

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[amyeroberts]

Thanks for fixing!