fix(deps): update gatsby monorepo

[renovate[bot]]

This PR contains the following updates:

Package	Type	Update	Change
gatsby (changelog)	dependencies	patch	2.22.15 -> 2.22.16
gatsby-source-filesystem	dependencies	patch	2.3.8 -> 2.3.9

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Release Notes

gatsbyjs/gatsby

### [`v2.22.16`](https://togithub.com/gatsbyjs/gatsby/compare/gatsby@2.22.15...gatsby@2.22.16) [Compare Source](https://togithub.com/gatsbyjs/gatsby/compare/gatsby@2.22.15...gatsby@2.22.16)

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