tests: add node 12, remove node 6

Author: igorklopov

package.json

@@ -62,7 +62,7 @@
     "lint": "eslint-klopov . || true",
     "prepare": "npm run babel",
     "prepublishOnly": "eslint-klopov . && npm run test:no-npm",
-    "test": "eslint-klopov . && npm run babel && node test/test.js node10 no-npm && node test/test.js node8 no-npm && node test/test.js node6 no-npm && node test/test.js host only-npm",
+    "test": "eslint-klopov . && npm run babel && node test/test.js node12 no-npm && node test/test.js node10 no-npm && node test/test.js node8 no-npm && node test/test.js host only-npm",
     "test:no-npm": "node test/test.js host no-npm"
   },
   "eslintConfig": {