Update dependency gatsby-theme-apollo-docs to v4.7.18

[renovate[bot]]

This PR contains the following updates:

Package	Change	Age	Adoption	Passing	Confidence
gatsby-theme-apollo-docs	4.7.16 -> 4.7.18

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Release Notes

apollographql/gatsby-theme-apollo

### [`v4.7.18`](https://togithub.com/apollographql/gatsby-theme-apollo/compare/gatsby-theme-apollo-docs@4.7.17...gatsby-theme-apollo-docs@4.7.18) [Compare Source](https://togithub.com/apollographql/gatsby-theme-apollo/compare/gatsby-theme-apollo-docs@4.7.17...gatsby-theme-apollo-docs@4.7.18) ### [`v4.7.17`](https://togithub.com/apollographql/gatsby-theme-apollo/compare/gatsby-theme-apollo-docs@4.7.16...gatsby-theme-apollo-docs@4.7.17) [Compare Source](https://togithub.com/apollographql/gatsby-theme-apollo/compare/gatsby-theme-apollo-docs@4.7.16...gatsby-theme-apollo-docs@4.7.17)

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Configuration

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