test: lock @vue/server-test-utils and @vue/test-utils version

Author: tangjinzhou

package.json

@@ -57,8 +57,8 @@
         "@commitlint/cli": "^6.2.0",
         "@commitlint/config-conventional": "^6.1.3",
         "@octokit/rest": "^15.4.1",
-        "@vue/server-test-utils": "^1.0.0-beta.16",
-        "@vue/test-utils": "^1.0.0-beta.16",
+        "@vue/server-test-utils": "1.0.0-beta.16",
+        "@vue/test-utils": "1.0.0-beta.16",
         "autoprefixer": "^8.1.0",
         "babel-cli": "^6.26.0",
         "babel-core": "^6.26.0",
@@ -166,4 +166,4 @@
         "shallowequal": "^1.0.2",
         "warning": "^3.0.0"
     }
-}
+}