Bump underscore from 1.9.0 to 1.13.1 in /website

Bumps [underscore](https://github.com/jashkenas/underscore) from 1.9.0 to 1.13.1.
- [Release notes](https://github.com/jashkenas/underscore/releases)
- [Commits](https://github.com/jashkenas/underscore/compare/1.9.0...1.13.1)

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

website/package-lock.json

@@ -8147,9 +8147,9 @@
       "integrity": "sha1-5z3T17DXxe2G+6xrCufYxqadUPo="
     },
     "underscore": {
-      "version": "1.9.0",
-      "resolved": "https://registry.npmjs.org/underscore/-/underscore-1.9.0.tgz",
-      "integrity": "sha512-4IV1DSSxC1QK48j9ONFK1MoIAKKkbE8i7u55w2R6IqBqbT7A/iG7aZBCR2Bi8piF0Uz+i/MG1aeqLwl/5vqF+A==",
+      "version": "1.13.1",
+      "resolved": "https://registry.npmjs.org/underscore/-/underscore-1.13.1.tgz",
+      "integrity": "sha512-hzSoAVtJF+3ZtiFX0VgfFPHEDRm7Y/QPjGyNo4TVdnDTdft3tr8hEkD25a1jC+TjTuE7tkHGKkhwCgs9dgBB2g==",
       "dev": true
     },
     "union-value": {