Update packages

package.json

@@ -8,11 +8,11 @@
     "gatsby-awesome-pagination": "^0.3.3",
     "gatsby-plugin-lodash": "^3.0.1",
     "gatsby-plugin-netlify": "^2.0.0",
-    "gatsby-plugin-purgecss": "^2.4.0",
+    "gatsby-plugin-purgecss": "^3.1.0",
     "gatsby-plugin-react-helmet": "^3.0.0",
     "gatsby-plugin-sass": "^2.0.1",
     "gatsby-plugin-sharp": "^2.0.5",
-    "gatsby-remark-images": "^2.0.1",
+    "gatsby-remark-images": "^3.0.3",
     "gatsby-source-filesystem": "^2.0.1",
     "gatsby-source-wordpress": "^3.0.1",
     "gatsby-transformer-remark": "^2.1.1",
@@ -37,7 +37,7 @@
   },
   "devDependencies": {
     "eslint-config-airbnb": "^17.1.0",
-    "eslint-config-prettier": "^3.1.0",
+    "eslint-config-prettier": "^4.0.0",
     "prettier": "^1.7.4",
     "rimraf": "^2.6.2"
   },