Bump gatsby-cli from 2.12.99 to 3.1.0

Bumps [gatsby-cli](https://github.com/gatsbyjs/gatsby/tree/HEAD/packages/gatsby-cli) from 2.12.99 to 3.1.0.
- [Release notes](https://github.com/gatsbyjs/gatsby/releases)
- [Changelog](https://github.com/gatsbyjs/gatsby/blob/master/packages/gatsby-cli/CHANGELOG.md)
- [Commits](https://github.com/gatsbyjs/gatsby/commits/gatsby-cli@3.1.0/packages/gatsby-cli)

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

package.json

@@ -7,7 +7,7 @@
     "@fec/gatsby-plugin-advanced-feed": "^1.1.0",
     "@reach/router": "^1.1.1",
     "gatsby": "^2.18.17",
-    "gatsby-cli": "^2.12.15",
+    "gatsby-cli": "^3.1.0",
     "gatsby-link": "^2.11.0",
     "gatsby-plugin-algolia-docsearch": "^1.0.5",
     "gatsby-plugin-csp": "^1.1.3",