ci: try using es5 for danger

Author: Barthelemy Ledoux

.travis.yml

@@ -34,6 +34,7 @@ jobs:
     - stage: test
       script:
         - npx danger ci
+      script:
         - yarn lint
         - yarn test:unit --runInBand
         - yarn test:e2e --headless

dangerfile.js

@@ -1,8 +1,7 @@
 /* eslint-disable */
-import * as fs from "fs";
-import * as path from "path";
-
-var validateMessage = require("validate-commit-msg");
+const fs = require("fs");
+const path = require("path");
+const validateMessage = require("validate-commit-msg");
 
 const packageChanged = danger.git.modified_files.includes("package.json");
 const lockfileChanged = danger.git.modified_files.includes("yarn.lock");