chore(deps): bump eta, @docusaurus/core and @docusaurus/preset-classic

Bumps [eta](https://github.com/eta-dev/eta) to 2.0.0 and updates ancestor dependencies [eta](https://github.com/eta-dev/eta), [@docusaurus/core](https://github.com/facebook/docusaurus/tree/HEAD/packages/docusaurus) and [@docusaurus/preset-classic](https://github.com/facebook/docusaurus/tree/HEAD/packages/docusaurus-preset-classic). These dependencies need to be updated together.


Updates `eta` from 1.12.3 to 2.0.0
- [Release notes](https://github.com/eta-dev/eta/releases)
- [Commits](https://github.com/eta-dev/eta/compare/v1.12.3...v2.0.0)

Updates `@docusaurus/core` from 2.1.0 to 2.3.1
- [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/v2.3.1/packages/docusaurus)

Updates `@docusaurus/preset-classic` from 2.1.0 to 2.3.1
- [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/v2.3.1/packages/docusaurus-preset-classic)

---
updated-dependencies:
- dependency-name: eta
  dependency-type: indirect
- dependency-name: "@docusaurus/core"
  dependency-type: direct:production
- dependency-name: "@docusaurus/preset-classic"
  dependency-type: direct:production
...

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

docs/package.json

@@ -15,8 +15,8 @@
     "typecheck": "tsc"
   },
   "dependencies": {
-    "@docusaurus/core": "^2.1.0",
-    "@docusaurus/preset-classic": "^2.1.0",
+    "@docusaurus/core": "^2.3.1",
+    "@docusaurus/preset-classic": "^2.3.1",
     "@fortawesome/fontawesome-svg-core": "^1.2.32",
     "@fortawesome/free-solid-svg-icons": "^5.15.3",
     "@fortawesome/react-fontawesome": "^0.1.18",