Bump lodash from 4.17.19 to 4.17.21 in /machine

Bumps [lodash](https://github.com/lodash/lodash) from 4.17.19 to 4.17.21.
- [Release notes](https://github.com/lodash/lodash/releases)
- [Commits](lodash/lodash@4.17.19...4.17.21)

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

machine/package.json

@@ -29,7 +29,7 @@
     "continuation-local-storage": "^3.1.7",
     "cors": "^2.7.1",
     "express": "^4.13.4",
-    "lodash": "^4.17.19",
+    "lodash": "^4.17.21",
     "md5-file": "^3.1.1",
     "mime": "^1.3.6",
     "morgan": "^1.7.0",