(doc) Fixed spelling mistake

[gep13]

Description

There is a spelling mistake in your nuspec file.

Motivation and Context

Once seen, it can't be unseen, and must be fixed!

How Has this Been Tested?

It hasn't. A minor change to the nuspec file, so no testing required.

Screenshot (if appropriate, usually isn't needed):

N/A

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)
• [ ] Migrated package (a package has been migrated from another repository)

Checklist:

• [x] My code follows the code style of this repository.
• [ ] My change requires a change to documentation (this usually means the notes in the description of a package).
• [ ] I have updated the documentation accordingly (this usually means the notes in the description of a package).
• [ ] I have updated the package description and it is less than 4000 characters.
• [x] All files are up to date with the latest Contributing Guidelines
• [ ] The added/modified package passed install/uninstall in the chocolatey test environment.
• [x] The changes only affect a single package (not including meta package).