fix(deps): update starters and examples - gatsby

[wardpeet]

This PR contains the following updates:

Package	Type	Update	Change
gatsby (changelog)	dependencies	minor	^3.6.2 -> ^3.7.0
gatsby-plugin-feed	dependencies	minor	^3.6.0 -> ^3.7.0
gatsby-plugin-gatsby-cloud	dependencies	minor	^2.6.1 -> ^2.7.0
gatsby-plugin-google-analytics	dependencies	minor	^3.6.0 -> ^3.7.0
gatsby-plugin-image	dependencies	minor	^1.6.0 -> ^1.7.0
gatsby-plugin-manifest	dependencies	minor	^3.6.0 -> ^3.7.0
gatsby-plugin-offline	dependencies	minor	^4.6.0 -> ^4.7.0
gatsby-plugin-react-helmet	dependencies	minor	^4.6.0 -> ^4.7.0
gatsby-plugin-sharp	dependencies	minor	^3.6.0 -> ^3.7.0
gatsby-source-filesystem	dependencies	minor	^3.6.0 -> ^3.7.0
gatsby-transformer-sharp	dependencies	minor	^3.6.0 -> ^3.7.0

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Release Notes

gatsbyjs/gatsby

v3.7.0

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