chore(deps-dev): bump typedoc-plugin-markdown from 4.2.8 to 4.2.9 in /docs (slackapi#2069)

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

docs/package-lock.json

@@ -30,7 +30,7 @@
     "@tsconfig/recommended": "^1.0.7",
     "docusaurus-plugin-typedoc": "^1.0.5",
     "typedoc": "^0.26.7",
-    "typedoc-plugin-markdown": "^4.2.8"
+    "typedoc-plugin-markdown": "^4.2.9"
   },
   "browserslist": {
     "production": [