Bump lodash from 4.17.15 to 4.17.21

Bumps [lodash](https://github.com/lodash/lodash) from 4.17.15 to 4.17.21.
- [Release notes](https://github.com/lodash/lodash/releases)
- [Commits](lodash/lodash@4.17.15...4.17.21)

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

Author: dependabot[bot]

package-lock.json

@@ -31,7 +31,7 @@
     "express": "^4.17.1",
     "express-session": "^1.16.2",
     "express-validator": "^6.2.0",
-    "lodash": "^4.17.15",
+    "lodash": "^4.17.21",
     "lusca": "^1.6.1"
   },
   "devDependencies": {