pin dependencies

package.json

@@ -77,7 +77,7 @@
     "babel-register": "6.18.0",
     "benchmark": "2.1.3",
     "browser-env": "2.0.31",
-    "eslint-config-prettier": "^2.1.0",
+    "eslint-config-prettier": "2.1.1",
     "gulp": "3.9.1",
     "gulp-babel": "6.1.2",
     "gulp-benchmark": "1.1.1",
@@ -85,7 +85,7 @@
     "husky": "^0.13.3",
     "lint-staged": "^3.4.2",
     "mz": "2.6.0",
-    "prettier": "^1.5.2",
+    "prettier": "1.5.2",
     "react": "15.4.1",
     "react-dom": "15.4.1",
     "xo": "0.18.2"