fix(deps): update gatsby monorepo

[renovate[bot]]

This PR contains the following updates:

Package	Type	Update	Change
gatsby (changelog)	dependencies	patch	2.24.85 -> 2.24.87
gatsby-source-contentful	dependencies	patch	3.0.3 -> 3.0.4
gatsby-source-filesystem	dependencies	patch	2.3.35 -> 2.3.36
gatsby-transformer-sharp	dependencies	patch	2.5.19 -> 2.5.20

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Release Notes

gatsbyjs/gatsby

### [`v2.24.87`](https://togithub.com/gatsbyjs/gatsby/compare/gatsby@2.24.86...gatsby@2.24.87) [Compare Source](https://togithub.com/gatsbyjs/gatsby/compare/gatsby@2.24.86...gatsby@2.24.87) ### [`v2.24.86`](https://togithub.com/gatsbyjs/gatsby/compare/gatsby@2.24.85...gatsby@2.24.86) [Compare Source](https://togithub.com/gatsbyjs/gatsby/compare/gatsby@2.24.85...gatsby@2.24.86)

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