chore(deps): update devdependency @vue/test-utils to v2

Author: renovate[bot]

package.json

@@ -68,7 +68,7 @@
     "@commitlint/config-conventional": "^7.1.2",
     "@nuxtjs/eslint-config": "0.0.1",
     "@vue/server-test-utils": "^1.0.0-beta",
-    "@vue/test-utils": "^1.0.0-beta",
+    "@vue/test-utils": "^2.4.4",
     "babel-core": "^6.26.3",
     "babel-eslint": "^10.0.1",
     "babel-jest": "^23.6.0",