Bump underscore from 1.9.1 to 1.12.1

Bumps [underscore](https://github.com/jashkenas/underscore) from 1.9.1 to 1.12.1.
- [Release notes](https://github.com/jashkenas/underscore/releases)
- [Commits](jashkenas/underscore@1.9.1...1.12.1)

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

package.json

@@ -181,7 +181,7 @@
     "swagger-tools": "0.10.1",
     "throng": "4.0.0",
     "uglifyify": "^3.0.4",
-    "underscore": "^1.9.1",
+    "underscore": "^1.12.1",
     "validator": "^4.0.2",
     "vinyl-source-stream": "^1.1.0",
     "webpack": "^1.12.10",