Pin dependencies (#561)

Author: renovate[bot]

package-lock.json

@@ -44,7 +44,7 @@
     "babel-core": "7.0.0-bridge.0",
     "babel-eslint": "10.0.1",
     "babel-loader": "8.0.6",
-    "chalk": "^2.4.2",
+    "chalk": "2.4.2",
     "classnames": "2.2.6",
     "clean-webpack-plugin": "2.0.2",
     "core-js": "2.6.5",
@@ -66,7 +66,7 @@
     "node-sass": "4.12.0",
     "po2json": "1.0.0-alpha",
     "postcss-loader": "3.0.0",
-    "progress-bar-webpack-plugin": "^1.12.1",
+    "progress-bar-webpack-plugin": "1.12.1",
     "react-test-renderer": "16.8.6",
     "rimraf": "2.6.3",
     "sass-loader": "7.1.0",