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

Author: renovate[bot]

.github/workflows/sync-csharp-sdk-docs.yaml

@@ -60,7 +60,7 @@ jobs:
           dotnet-version: "9.0.x"
 
       - name: Set up Python
-        uses: actions/setup-python@v5
+        uses: actions/setup-python@v6
         with:
           python-version: "3.14"
 

.github/workflows/sync-python-sdk-docs.yaml

@@ -60,7 +60,7 @@ jobs:
           version: "latest"
 
       - name: Set up Python
-        uses: actions/setup-python@v5
+        uses: actions/setup-python@v6
         with:
           python-version: "3.14"