Bump markdown-it-footnote from 3.0.3 to 4.0.0

Bumps [markdown-it-footnote](https://github.com/markdown-it/markdown-it-footnote) from 3.0.3 to 4.0.0.
- [Changelog](https://github.com/markdown-it/markdown-it-footnote/blob/master/CHANGELOG.md)
- [Commits](markdown-it/markdown-it-footnote@3.0.3...4.0.0)

---
updated-dependencies:
- dependency-name: markdown-it-footnote
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

package.json

@@ -30,7 +30,7 @@
 		"markdown-it": "^13.0.2",
 		"markdown-it-anchor": "^8.6.7",
 		"markdown-it-attrs": "^4.1.6",
-		"markdown-it-footnote": "^3.0.3",
+		"markdown-it-footnote": "^4.0.0",
 		"netlify-plugin-cache-folder": "^0.0.8",
 		"title-case": "^3.0.3"
 	}