fix(deps): update gatsby monorepo

Author: renovate-bot

package-lock.json

@@ -7,13 +7,13 @@
     "@types/react-helmet": "6.1.0",
     "@types/typography": "0.16.3",
     "gatsby": "2.28.2",
-    "gatsby-image": "2.7.0",
+    "gatsby-image": "2.8.0",
     "gatsby-plugin-manifest": "2.8.0",
     "gatsby-plugin-offline": "3.6.0",
-    "gatsby-plugin-react-helmet": "3.6.0",
-    "gatsby-plugin-sass": "2.7.0",
+    "gatsby-plugin-react-helmet": "3.7.0",
+    "gatsby-plugin-sass": "2.8.0",
     "gatsby-plugin-sharp": "2.10.1",
-    "gatsby-plugin-typography": "2.8.0",
+    "gatsby-plugin-typography": "2.9.0",
     "gatsby-source-filesystem": "2.7.0",
     "gatsby-transformer-sharp": "2.8.0",
     "node-sass": "4.14.1",