fix(ci): upgrade to Node 22 to fix katex __VERSION__ crash in mint CLI

The mint CLI >=4.2.404 ships a katex version whose ESM entry point
references an unbundled __VERSION__ constant. Node 20 throws
'ReferenceError: __VERSION__ is not defined'; Node 22 handles this
correctly. Upgrade the CI from Node 20 → 22 so we can keep using
mint@latest.

Co-authored-by: openhands <openhands@all-hands.dev>

Author: openhands-agent

.github/workflows/check-broken-links.yml

@@ -34,7 +34,7 @@ jobs:
       - name: Setup Node.js
         uses: actions/setup-node@v4
         with:
-          node-version: '20'
+          node-version: '22'
 
       - name: Install Mint CLI
         run: npm install -g mint@latest