docs: fix typo

[tbroadley]

This PR fixes a typo in README.md.

Types of changes

• [x] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)

Related Issue

There is no related issue - I hope that's alright for a typo fix!

[coveralls]

Pull Request Test Coverage Report for Build 42

• 0 of 0 (NaN%) changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 97.895%

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Totals
Change from base Build 38:	0.0%
Covered Lines:	66
Relevant Lines:	66

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💛 - Coveralls

[tollmanz]

Nice catch, @tbroadley! I really appreciate you taking the time to fix this.

[tbroadley]

Happy to help @tollmanz!