fix: use correct unist-util-visit-parents imports (#1427)

The recent `unist-util-visit-parents` renovate update broke the
`changelogFromRoot` theme option (and therefore e.g. [Apify Python SDK
changelog](https://docs.apify.com/sdk/python/docs/changelog)). Even
though the `unist` package claims to be ESM-only, this fix seems to
remedy the issues.

Author: barjin

apify-docs-theme/src/markdown.js

@@ -1,7 +1,7 @@
 const remarkParse = require('remark-parse');
 const remarkStringify = require('remark-stringify');
 const { unified } = require('unified');
-const visitParents = require('unist-util-visit-parents');
+const { visitParents } = require('unist-util-visit-parents');
 
 /**
  * Updates the markdown content for better UX and compatibility with Docusaurus v3.