chore:fix typo in contributing

[thuvh]

What kind of change does this PR introduce?

docs

What is the current behavior?

n/a

What is the new behavior?

fix typo

Additional context

n/a

[cstockton]

Good catch, thank you!

[coveralls]

Pull Request Test Coverage Report for Build 12901329548

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

• For more information on this, see Tracking coverage changes with pull request builds.
• To avoid this issue with future PRs, see these Recommended CI Configurations.
• For a quick fix, rebase this PR at GitHub. Your next report should be accurate.

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 65.445%

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Totals
Change from base Build 12806215187:	0.0%
Covered Lines:	9818
Relevant Lines:	15002

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💛 - Coveralls