chore(deps): update actions/checkout action to v6

Author: renovate[bot]

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

@@ -42,13 +42,13 @@ jobs:
           fi
 
       - name: Checkout camunda-docs
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
         with:
           repository: camunda/camunda-docs
           path: docs
 
       - name: Checkout C# SDK
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
         with:
           repository: camunda/orchestration-cluster-api-csharp
           ref: ${{ steps.resolve.outputs.sdk_ref }}

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

@@ -42,13 +42,13 @@ jobs:
           fi
 
       - name: Checkout camunda-docs
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
         with:
           repository: camunda/camunda-docs
           path: docs
 
       - name: Checkout Python SDK
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
         with:
           repository: camunda/orchestration-cluster-api-python
           ref: ${{ steps.resolve.outputs.sdk_ref }}

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

@@ -42,13 +42,13 @@ jobs:
           fi
 
       - name: Checkout camunda-docs
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
         with:
           repository: camunda/camunda-docs
           path: docs
 
       - name: Checkout TypeScript SDK
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
         with:
           repository: camunda/orchestration-cluster-api-js
           ref: ${{ steps.resolve.outputs.sdk_ref }}