fix(deps): update gatsby monorepo

[renovate[bot]]

This PR contains the following updates:

Package	Change	Age	Adoption	Passing	Confidence
gatsby-plugin-sharp	2.13.3 -> 2.13.4
gatsby-source-contentful	4.5.2 -> 4.5.3

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Release Notes

gatsbyjs/gatsby

### [`v2.13.4`](https://togithub.com/gatsbyjs/gatsby/compare/gatsby@2.13.3...gatsby@2.13.4) [Compare Source](https://togithub.com/gatsbyjs/gatsby/compare/4e4b1edb216aac131040097ef8465b05cd8cf87f...a777f9fb9a249553f2b21e94b24bfb4d3eabedae)

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