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.json

@@ -42,7 +42,7 @@
     "bluebird": "3.7.2",
     "humps": "2.0.1",
     "js-md5": "0.7.3",
-    "lodash": "4.17.15",
+    "lodash": "4.17.21",
     "mqtt": "2.18.8",
     "stompjs": "git://github.com/gfoiani/stomp-websocket.git#2.4.0",
     "url-join": "4.0.1",

yarn.lock

@@ -3908,15 +3908,10 @@ lodash.assign@^4.0.3, lodash.assign@^4.0.6:
   resolved "https://registry.yarnpkg.com/lodash.assign/-/lodash.assign-4.2.0.tgz#0d99f3ccd7a6d261d19bdaeb9245005d285808e7"
   integrity sha1-DZnzzNem0mHRm9rrkkUAXShYCOc=
 
-lodash@4.17.15, lodash@^4.17.14, lodash@^4.17.15:
-  version "4.17.15"
-  resolved "https://registry.yarnpkg.com/lodash/-/lodash-4.17.15.tgz#b447f6670a0455bbfeedd11392eff330ea097548"
-  integrity sha512-8xOcRHvCjnocdS5cpwXQXVzmmh5e5+saE2QGoeQmbKmRS6J3VQppPOIt0MnmE+4xlZoumy0GPG0D0MVIQbNA1A==
-
-lodash@^4.17.11, lodash@^4.17.4, lodash@^4.2.0:
-  version "4.17.11"
-  resolved "https://registry.yarnpkg.com/lodash/-/lodash-4.17.11.tgz#b39ea6229ef607ecd89e2c8df12536891cac9b8d"
-  integrity sha512-cQKh8igo5QUhZ7lg38DYWAxMvjSAKG0A8wGSVimP07SIUEK2UO+arSRKbRZWtelMtN5V0Hkwh5ryOto/SshYIg==
+lodash@4.17.21, lodash@^4.17.11, lodash@^4.17.14, lodash@^4.17.15, lodash@^4.17.4, lodash@^4.2.0:
+  version "4.17.21"
+  resolved "https://registry.yarnpkg.com/lodash/-/lodash-4.17.21.tgz#679591c564c3bffaae8454cf0b3df370c3d6911c"
+  integrity sha512-v2kDEe57lecTulaDIuNTPy3Ry4gLGJ6Z1O3vE1krgXZNrsQ+LFTGHVxVjcXPs17LhbZVGedAJv8XZ1tvj5FvSg==
 
 loose-envify@^1.0.0:
   version "1.4.0"