Bump @docusaurus/core in /packages/website

Bumps [@docusaurus/core](https://github.com/facebook/docusaurus/tree/HEAD/packages/docusaurus) from 2.0.0-beta.15 to 2.0.0-beta.17.
- [Release notes](https://github.com/facebook/docusaurus/releases)
- [Changelog](https://github.com/facebook/docusaurus/blob/main/CHANGELOG.md)
- [Commits](https://github.com/facebook/docusaurus/commits/v2.0.0-beta.17/packages/docusaurus)

---
updated-dependencies:
- dependency-name: "@docusaurus/core"
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

packages/website/package.json

@@ -9,7 +9,7 @@
     "all": "yarn build"
   },
   "dependencies": {
-    "@docusaurus/core": "2.0.0-beta.15",
+    "@docusaurus/core": "2.0.0-beta.17",
     "@docusaurus/preset-classic": "2.0.0-beta.17",
     "@mdx-js/react": "^1.6.21",
     "clsx": "^1.1.1",