fix: update README.md

[jleach]

Summary of Changes

Fix installation instructions for anyone outside of the Bifold project.

Related Issues

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• All commits contain a DCO Signed-off-by line (we use the DCO GitHub app to enforce this);
• Updated LICENSE-3RD-PARTY.md for any added dependencies or vendored components;
• Updated documentation as needed for changed code and new or modified features;
• Added sufficient tests so that overall code coverage is not reduced.

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