Update dependency nyc to v15.0.1

[renovate[bot]]

This PR contains the following updates:

Package	Type	Update	Change
nyc (source)	devDependencies	patch	15.0.0 -> 15.0.1

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Release Notes

istanbuljs/nyc

### [`v15.0.1`](https://togithub.com/istanbuljs/nyc/blob/master/CHANGELOG.md#​1501-httpsgithubcomistanbuljsnyccomparev1500v1501-2020-04-02) [Compare Source](https://togithub.com/istanbuljs/nyc/compare/v15.0.0...v15.0.1)

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