build(deps): bump lodash from 4.17.11 to 4.17.15

Bumps [lodash](https://github.com/lodash/lodash) from 4.17.11 to 4.17.15.
- [Release notes](https://github.com/lodash/lodash/releases)
- [Commits](https://github.com/lodash/lodash/compare/4.17.11...4.17.15)

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

package.json

@@ -27,7 +27,7 @@
     "grunt-contrib-jade": "^1.0.0",
     "grunt-contrib-uglify": "^4.0.0",
     "jade": "^1.11.0",
-    "lodash": "4.17.11",
+    "lodash": "4.17.15",
     "primus": "^7.3.1",
     "primus-emit": "^1.0.0",
     "primus-spark-latency": "^0.1.1",