chore(deps): update dependency tap to v21

Author: renovate[bot]

package.json

@@ -72,7 +72,7 @@
     "rimraf": "^2.2.8",
     "server-destroy": "^1.0.1",
     "standard": "^9.0.0",
-    "tap": "^15.1.5",
+    "tap": "^21.0.0",
     "tape": "^4.6.0"
   },
   "greenkeeper": {