[eslint config] [tests] Even though the base config may not be up to …

…date in the main package, let’s `npm link` the base package into the main one for the sake of travis-ci tests.

package.json

@@ -4,7 +4,7 @@
   "description": "A mostly reasonable approach to JavaScript.",
   "scripts": {
     "preinstall": "npm run install:config && npm run install:config:base",
-    "install:config": "cd packages/eslint-config-airbnb && npm install",
+    "install:config": "cd packages/eslint-config-airbnb && npm install && npm install ../eslint-config-airbnb-base",
     "install:config:base": "cd packages/eslint-config-airbnb-base && npm install",
     "test": "npm run --silent test:config && npm run --silent test:config:base",
     "test:config": "cd packages/eslint-config-airbnb; npm test",