chore(deps): update actions/setup-node action to v6

Author: renovate[bot]

.github/workflows/python_docs_check.yaml

@@ -22,7 +22,7 @@ jobs:
         uses: actions/checkout@v6
 
       - name: Set up Node
-        uses: actions/setup-node@v4
+        uses: actions/setup-node@v6
         with:
           node-version: ${{ inputs.node_version }}
 

.github/workflows/tests.yaml

@@ -119,7 +119,7 @@ jobs:
 
       # TODO: turn on caching
       - name: setup Node.js
-        uses: actions/setup-node@v4
+        uses: actions/setup-node@v6
         with:
           always-auth: ${{ inputs.npmAuth }}
           node-version-file: ${{ inputs.nodeVersionFile }}