chore(deps): bump @docusaurus/preset-classic in /docs

Bumps [@docusaurus/preset-classic](https://github.com/facebook/docusaurus/tree/HEAD/packages/docusaurus-preset-classic) from 2.0.0-beta.1 to 2.0.0-beta.3.
- [Release notes](https://github.com/facebook/docusaurus/releases)
- [Changelog](https://github.com/facebook/docusaurus/blob/master/CHANGELOG.md)
- [Commits](https://github.com/facebook/docusaurus/commits/v2.0.0-beta.3/packages/docusaurus-preset-classic)

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

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

docs/package.json

@@ -15,7 +15,7 @@
   },
   "dependencies": {
     "@docusaurus/core": "^2.0.0-beta.1",
-    "@docusaurus/preset-classic": "^2.0.0-beta.1",
+    "@docusaurus/preset-classic": "^2.0.0-beta.3",
     "@fortawesome/fontawesome-svg-core": "^1.2.32",
     "@fortawesome/free-solid-svg-icons": "^5.15.3",
     "@fortawesome/react-fontawesome": "^0.1.14",