Fix test:coverage command

Author: voxpelli

package.json

@@ -8,7 +8,7 @@
     "lint": "standard | snazzy",
     "lint:fix": "standard --fix",
     "test": "npm run test:unit && npm run test:typescript",
-    "test:coverage": "npm run unit -- --cov --coverage-report=html",
+    "test:coverage": "npm run test:unit -- --cov --coverage-report=html",
     "test:typescript": "tsd",
     "test:unit": "tap"
   },