add --check-files to netlify install

package.json

@@ -84,7 +84,7 @@
     "format:source": "prettier --config .prettierrc --write \"{gatsby-*.js,{flow-typed,plugins,src}/**/*.js}\"",
     "format:examples": "prettier --config .prettierrc.examples --write \"examples/**/*.js\"",
     "lint": "eslint .",
-    "netlify": "yarn install && yarn build",
+    "netlify": "yarn install --check-files && yarn build",
     "nit:source": "prettier --config .prettierrc --list-different \"{gatsby-*.js,{flow-typed,plugins,src}/**/*.js}\"",
     "nit:examples": "prettier --config .prettierrc.examples --list-different \"examples/**/*.js\"",
     "prettier": "yarn format:source && yarn format:examples",