chore(deps): update dependency markdownlint-cli2 to v0.20.0

| datasource | package           | from   | to     |
| ---------- | ----------------- | ------ | ------ |
| npm        | markdownlint-cli2 | 0.19.0 | 0.20.0 |

Author: renovate[bot]

package-lock.json

@@ -50,7 +50,7 @@
   "devDependencies": {
     "@types/node": "^24.10.1",
     "@vitest/ui": "^4.0.15",
-    "markdownlint-cli2": "0.19.0",
+    "markdownlint-cli2": "0.20.0",
     "prettier": "3.6.2",
     "typescript": "^5.9.3",
     "vitest": "^4.0.15"