Bump gatsby-transformer-sharp from 2.5.20 to 2.7.0

Bumps [gatsby-transformer-sharp](https://github.com/gatsbyjs/gatsby/tree/HEAD/packages/gatsby-transformer-sharp) from 2.5.20 to 2.7.0.
- [Release notes](https://github.com/gatsbyjs/gatsby/releases)
- [Changelog](https://github.com/gatsbyjs/gatsby/blob/master/packages/gatsby-transformer-sharp/CHANGELOG.md)
- [Commits](https://github.com/gatsbyjs/gatsby/commits/gatsby-transformer-sharp@2.7.0/packages/gatsby-transformer-sharp)

Signed-off-by: dependabot[bot] <support@github.com>

package.json

@@ -77,7 +77,7 @@
     "gatsby-plugin-sitemap": "^2.7.0",
     "gatsby-plugin-svgr": "^2.0.2",
     "gatsby-source-filesystem": "^2.5.0",
-    "gatsby-transformer-sharp": "^2.5.19",
+    "gatsby-transformer-sharp": "^2.7.0",
     "isomorphic-fetch": "^3.0.0",
     "moment": "^2.29.1",
     "postcss-calc": "^7.0.2",