Update actions/checkout action to v6 (#3657)

Author: renovate[bot]

.github/workflows/docs.yaml

@@ -16,7 +16,7 @@ jobs:
 
     steps:
     - name: Check out current revision
-      uses: actions/checkout@v5
+      uses: actions/checkout@v6
       with:
         fetch-depth: 0
 

.github/workflows/main.yml

@@ -35,7 +35,7 @@ jobs:
     runs-on: ubuntu-24.04
 
     steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
 
     - name: Fetch tip of main branch to support diffing
       run: git fetch --depth 1 origin main

.github/workflows/scripts.yml

@@ -15,7 +15,7 @@ jobs:
     runs-on: ubuntu-24.04
 
     steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
 
     - name: Set up Python
       uses: actions/setup-python@v6