Bump @docusaurus/core from 2.0.0-alpha.71 to 2.0.0-alpha.72 (#478)

* Bump @docusaurus/core from 2.0.0-alpha.71 to 2.0.0-alpha.72

Bumps [@docusaurus/core](https://github.com/facebook/docusaurus/tree/HEAD/packages/docusaurus) from 2.0.0-alpha.71 to 2.0.0-alpha.72.
- [Release notes](https://github.com/facebook/docusaurus/releases)
- [Changelog](https://github.com/facebook/docusaurus/blob/master/CHANGELOG-2.x.md)
- [Commits](https://github.com/facebook/docusaurus/commits/v2.0.0-alpha.72/packages/docusaurus)

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

* Bump preset classic

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Tom Brien <tom@byth.co.uk>

package.json

@@ -12,8 +12,8 @@
   },
   "dependencies": {
     "by-node-env": "^2.0.1",
-    "@docusaurus/preset-classic": "^2.0.0-alpha.71",
-    "@docusaurus/core": "^2.0.0-alpha.71",
+    "@docusaurus/preset-classic": "^2.0.0-alpha.72",
+    "@docusaurus/core": "^2.0.0-alpha.72",
     "@mdx-js/react": "^1.6.21",
     "clsx": "^1.1.1",
     "react": "^17.0.1",