fix(starters): update gatsby monorepo

Author: renovate-bot

starters/blog/package-lock.json

@@ -8,11 +8,11 @@
     "url": "https://github.com/gatsbyjs/gatsby/issues"
   },
   "dependencies": {
-    "gatsby": "^2.3.3",
+    "gatsby": "^2.3.4",
     "gatsby-image": "^2.0.35",
     "gatsby-plugin-feed": "^2.1.0",
     "gatsby-plugin-google-analytics": "^2.0.18",
-    "gatsby-plugin-manifest": "^2.0.25",
+    "gatsby-plugin-manifest": "^2.0.26",
     "gatsby-plugin-offline": "^2.0.25",
     "gatsby-plugin-react-helmet": "^3.0.11",
     "gatsby-plugin-sharp": "^2.0.32",