build(deps): bump @docusaurus/preset-classic in /docs (#3871)

Bumps [@docusaurus/preset-classic](https://github.com/facebook/docusaurus/tree/HEAD/packages/docusaurus-preset-classic) from 2.0.0-alpha.74 to 2.0.0-alpha.75.
- [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-alpha.75/packages/docusaurus-preset-classic)

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

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

docs/package.json

@@ -13,7 +13,7 @@
   },
   "dependencies": {
     "@docusaurus/core": "^2.0.0-alpha.74",
-    "@docusaurus/preset-classic": "^2.0.0-alpha.74",
+    "@docusaurus/preset-classic": "^2.0.0-alpha.75",
     "clsx": "^1.1.1",
     "react": "^17.0.2",
     "react-dom": "^17.0.2"