Bump lodash from 4.17.11 to 4.17.15 in /website (#2233)

Summary:
Bumps [lodash](https://github.com/lodash/lodash) from 4.17.11 to 4.17.15.
<details>
<summary>Commits</summary>

- [`ddfd9b1`](lodash/lodash@ddfd9b1) Bump to v4.17.15.
- [`b185fce`](lodash/lodash@b185fce) Rebuild lodash and docs.
- [`be87d30`](lodash/lodash@be87d30) Bump to v4.17.14.
- [`a6fe6b1`](lodash/lodash@a6fe6b1) Rebuild lodash and docs.
- [`e371828`](lodash/lodash@e371828) Bump to v4.17.13.
- [`357e899`](lodash/lodash@357e899) Rebuild lodash and docs.
- [`fd9a062`](lodash/lodash@fd9a062) Bump to v4.17.12.
- [`e77d681`](lodash/lodash@e77d681) Rebuild lodash and docs.
- [`629d186`](lodash/lodash@629d186) Update OpenJS references.
- [`2406eac`](lodash/lodash@2406eac) Fix minified build.
- Additional commits viewable in [compare view](lodash/lodash@4.17.11...4.17.15)
</details>
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</details>
Pull Request resolved: #2233

Reviewed By: elboman

Differential Revision: D18220755

Pulled By: mrkev

fbshipit-source-id: 15c655b4490baf64a98bcf51e660a6bf2a152261

website/yarn.lock

@@ -3556,9 +3556,9 @@ lodash.uniq@^4.5.0:
   integrity sha1-0CJTc662Uq3BvILklFM5qEJ1R3M=
 
 lodash@^4.17.4, lodash@^4.3.0, lodash@~4.17.10:
-  version "4.17.11"
-  resolved "https://registry.yarnpkg.com/lodash/-/lodash-4.17.11.tgz#b39ea6229ef607ecd89e2c8df12536891cac9b8d"
-  integrity sha512-cQKh8igo5QUhZ7lg38DYWAxMvjSAKG0A8wGSVimP07SIUEK2UO+arSRKbRZWtelMtN5V0Hkwh5ryOto/SshYIg==
+  version "4.17.15"
+  resolved "https://registry.yarnpkg.com/lodash/-/lodash-4.17.15.tgz#b447f6670a0455bbfeedd11392eff330ea097548"
+  integrity sha512-8xOcRHvCjnocdS5cpwXQXVzmmh5e5+saE2QGoeQmbKmRS6J3VQppPOIt0MnmE+4xlZoumy0GPG0D0MVIQbNA1A==
 
 logalot@^2.0.0:
   version "2.1.0"