fix(@vue/cli-service): Update lodash.defaultsdeep (#4273)

Update `lodash.defaultsdeep` to version `^4.6.1`.

This is causing a high severity vulnerability in our repo.

Fixed in lodash/lodash#4336.

(cherry picked from commit 4267b54)

Author: emizzle

packages/@vue/cli-service/package.json

@@ -55,7 +55,7 @@
     "hash-sum": "^1.0.2",
     "html-webpack-plugin": "^3.2.0",
     "launch-editor-middleware": "^2.2.1",
-    "lodash.defaultsdeep": "^4.6.0",
+    "lodash.defaultsdeep": "^4.6.1",
     "lodash.mapvalues": "^4.6.0",
     "lodash.transform": "^4.6.0",
     "mini-css-extract-plugin": "^0.6.0",