fix(deps): update gatsby monorepo (#986)

Co-authored-by: Renovate Bot <[email protected]>

package.json

@@ -59,7 +59,7 @@
     "eslint-plugin-mdx": "1.6.8",
     "eslint-plugin-prettier": "3.1.2",
     "eslint-plugin-react": "7.19.0",
-    "gatsby": "2.19.39",
+    "gatsby": "2.20.7",
     "hast-util-select": "4.0.0",
     "husky": "4.2.3",
     "jest": "25.1.0",

packages/gatsby-theme-mdx/package.json

@@ -30,17 +30,17 @@
     "@reach/skip-nav": "0.8.6",
     "@rebass/emotion": "3.2.0",
     "@theme-ui/preset-system": "0.3.0",
-    "gatsby": "2.19.39",
-    "gatsby-plugin-catch-links": "2.1.27",
+    "gatsby": "2.20.7",
+    "gatsby-plugin-catch-links": "2.2.1",
     "gatsby-plugin-compile-es6-packages": "2.1.0",
-    "gatsby-plugin-emotion": "4.1.24",
+    "gatsby-plugin-emotion": "4.2.1",
     "gatsby-plugin-fathom": "1.2.0",
     "gatsby-plugin-google-fonts": "1.0.1",
-    "gatsby-plugin-mdx": "1.0.80",
-    "gatsby-plugin-page-creator": "2.1.45",
-    "gatsby-plugin-react-helmet": "3.1.23",
+    "gatsby-plugin-mdx": "1.1.3",
+    "gatsby-plugin-page-creator": "2.2.1",
+    "gatsby-plugin-react-helmet": "3.2.1",
     "gatsby-plugin-theme-ui": "0.3.0",
-    "gatsby-source-filesystem": "2.1.53",
+    "gatsby-source-filesystem": "2.2.2",
     "is-absolute-url": "3.0.3",
     "lodash.flatten": "4.4.0",
     "prism-react-renderer": "1.0.2",