Attempt to fix Jest in CI conforming to jestjs/jest#6393 (comment)

Author: mdvanes

package.json

@@ -18,7 +18,7 @@
     "i18next": "^11.3.2",
     "i18next-browser-languagedetector": "^2.2.0",
     "i18next-xhr-backend": "^1.5.1",
-    "jest-cli": "^23.4.1",
+    "jest-cli": "^20.0.4",
     "lint-staged": "^7.0.0",
     "lodash": "^4.17.10",
     "nuka-carousel": "^4.2.5",