Bump lodash from 4.17.4 to 4.17.21 in /intro/server

Bumps [lodash](https://github.com/lodash/lodash) from 4.17.4 to 4.17.21.
- [Release notes](https://github.com/lodash/lodash/releases)
- [Commits](https://github.com/lodash/lodash/compare/4.17.4...4.17.21)

Signed-off-by: dependabot[bot] <support@github.com>

intro/server/package.json

@@ -22,7 +22,7 @@
   "dependencies": {
     "bcrypt-nodejs": "0.0.3",
     "jsonwebtoken": "8.1.0",
-    "lodash": "4.17.4",
+    "lodash": "4.17.21",
     "moleculer": "^0.11.0",
     "moleculer-db": "0.7.0",
     "moleculer-db-adapter-mongo": "0.1.6",