Disable markdown-it types update (#2327)

# Pull Request

## 🤨 Rationale

The `@types/markdown-it` updates were disabled due to an issue in
prosemirror-markdown. See #2326

## 👩‍💻 Implementation

Disabled `@types/markdown-it` in the renovate config.

## 🧪 Testing

Will see if the renovate merge PR is successful after.

## ✅ Checklist

- [x] I have updated the project documentation to reflect my changes or
determined no changes are needed.

.github/renovate.json

@@ -27,6 +27,7 @@
       "matchDepTypes": ["dependencies", "devDependencies", "peerDependencies"],
       "excludePackagePatterns":[
         "^@angular",
+        "@types/markdown-it",
         "apache-arrow",
         "comlink",
         "eslint",