fix(deps): update gatsby monorepo (#944)

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

package.json

@@ -59,7 +59,7 @@
     "eslint-plugin-mdx": "1.6.8",
     "eslint-plugin-prettier": "3.1.2",
     "eslint-plugin-react": "7.18.3",
-    "gatsby": "^2.19.5",
+    "gatsby": "2.19.15",
     "hast-util-select": "3.0.1",
     "husky": "4.2.1",
     "jest": "25.1.0",

packages/gatsby-theme-mdx/package.json

@@ -29,17 +29,17 @@
     "@reach/router": "1.2.1",
     "@reach/skip-nav": "0.7.4",
     "@rebass/emotion": "3.2.0",
-    "gatsby": "^2.19.5",
-    "gatsby-plugin-catch-links": "2.1.24",
+    "gatsby": "2.19.15",
+    "gatsby-plugin-catch-links": "2.1.25",
     "gatsby-plugin-compile-es6-packages": "2.1.0",
-    "gatsby-plugin-emotion": "4.1.21",
+    "gatsby-plugin-emotion": "4.1.22",
     "gatsby-plugin-fathom": "1.2.0",
     "gatsby-plugin-google-fonts": "1.0.1",
-    "gatsby-plugin-mdx": "1.0.67",
-    "gatsby-plugin-page-creator": "2.1.38",
-    "gatsby-plugin-react-helmet": "3.1.21",
+    "gatsby-plugin-mdx": "1.0.71",
+    "gatsby-plugin-page-creator": "2.1.40",
+    "gatsby-plugin-react-helmet": "3.1.22",
     "gatsby-plugin-theme-ui": "0.3.0",
-    "gatsby-source-filesystem": "2.1.46",
+    "gatsby-source-filesystem": "2.1.48",
     "is-absolute-url": "3.0.3",
     "lodash.flatten": "4.4.0",
     "prism-react-renderer": "1.0.2",