[infer][PR] Bump acorn from 6.4.0 to 6.4.1 in /website

Summary:
Bumps [acorn](https://github.com/acornjs/acorn) from 6.4.0 to 6.4.1.
<details>
<summary>Commits</summary>
<ul>
<li><a href="9a2e9b6678"><code>9a2e9b6</code></a> Mark version 6.4.1</li>
<li><a href="90a9548ea0"><code>90a9548</code></a> More rigorously check surrogate pairs in regexp validator</li>
<li>See full diff in <a href="https://github.com/acornjs/acorn/compare/6.4.0...6.4.1">compare view</a></li>
</ul>
</details>
<br />

[![Dependabot compatibility score](https://dependabot-badges.githubapp.com/badges/compatibility_score?dependency-name=acorn&package-manager=npm_and_yarn&previous-version=6.4.0&new-version=6.4.1)](https://help.github.com/articles/configuring-automated-security-fixes)

Dependabot will resolve any conflicts with this PR as long as you don't alter it yourself. You can also trigger a rebase manually by commenting `dependabot rebase`.

[//]: # (dependabot-automerge-start)
[//]: # (dependabot-automerge-end)

 ---

<details>
<summary>Dependabot commands and options</summary>
<br />

You can trigger Dependabot actions by commenting on this PR:
- `dependabot rebase` will rebase this PR
- `dependabot recreate` will recreate this PR, overwriting any edits that have been made to it
- `dependabot merge` will merge this PR after your CI passes on it
- `dependabot squash and merge` will squash and merge this PR after your CI passes on it
- `dependabot cancel merge` will cancel a previously requested merge and block automerging
- `dependabot reopen` will reopen this PR if it is closed
- `dependabot close` will close this PR and stop Dependabot recreating it. You can achieve the same result by closing it manually
- `dependabot ignore this major version` will close this PR and stop Dependabot creating any more for this major version (unless you reopen the PR or upgrade to it yourself)
- `dependabot ignore this minor version` will close this PR and stop Dependabot creating any more for this minor version (unless you reopen the PR or upgrade to it yourself)
- `dependabot ignore this dependency` will close this PR and stop Dependabot creating any more for this dependency (unless you reopen the PR or upgrade to it yourself)
- `dependabot use these labels` will set the current labels as the default for future PRs for this repo and language
- `dependabot use these reviewers` will set the current reviewers as the default for future PRs for this repo and language
- `dependabot use these assignees` will set the current assignees as the default for future PRs for this repo and language
- `dependabot use this milestone` will set the current milestone as the default for future PRs for this repo and language

You can disable automated security fix PRs for this repo from the [Security Alerts page](https://github.com/facebook/infer/network/alerts).

</details>
Pull Request resolved: https://github.com/facebook/infer/pull/1238

Reviewed By: dulmarod

Differential Revision: D20513549

Pulled By: jvillard

fbshipit-source-id: 92cc20052

website/yarn.lock

@@ -1331,9 +1331,9 @@ acorn-walk@^6.1.1:
   integrity sha512-7evsyfH1cLOCdAzZAd43Cic04yKydNx0cF+7tiA19p1XnLLPU4dpCQOqpjqwokFe//vS0QqfqqjCS2JkiIs0cA==
 
 acorn@^6.0.7, acorn@^6.2.1:
-  version "6.4.0"
-  resolved "https://registry.yarnpkg.com/acorn/-/acorn-6.4.0.tgz#b659d2ffbafa24baf5db1cdbb2c94a983ecd2784"
-  integrity sha512-gac8OEcQ2Li1dxIEWGZzsp2BitJxwkwcOm0zHAJLcPJaVvm58FRnk6RkuLRpU1EujipU2ZFODv2P9DLMfnV8mw==
+  version "6.4.1"
+  resolved "https://registry.yarnpkg.com/acorn/-/acorn-6.4.1.tgz#531e58ba3f51b9dacb9a6646ca4debf5b14ca474"
+  integrity sha512-ZVA9k326Nwrj3Cj9jlh3wGFutC2ZornPNARZwsNYqQYgN0EsV2d53w5RN/co65Ohn4sUAUtb1rSUAOD6XN9idA==
 
 address@1.1.2, address@^1.0.1:
   version "1.1.2"