Update actions/checkout action to v6

Author: renovate[bot]

.github/actions/smoke-test/action.yaml

@@ -9,7 +9,7 @@ runs:
   steps:
     - name: Checkout main
       id: checkout_release
-      uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
+      uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
 
     - name: Build template
       id: build_template

.github/workflows/build-base.yaml

@@ -32,7 +32,7 @@ jobs:
           - "nixos-unstable"
           - "nixos-25.11"
     steps:
-      - uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
+      - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
 
       - name: Set up PATH for NixOS (self-hosted)
         if: matrix.nix_system == 'aarch64-linux'
@@ -82,7 +82,7 @@ jobs:
     needs:
       - build
     steps:
-      - uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
+      - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       - name: Login to Registry
         uses: docker/login-action@v3
         with:

.github/workflows/build-push-latest-flake.yaml

@@ -38,7 +38,7 @@ jobs:
             home_manager_channel: "https://github.com/nix-community/home-manager/archive/release-25.11.tar.gz"
             default_tag: true
     steps:
-      - uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
+      - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       - name: Set up QEMU
         uses: docker/setup-qemu-action@v3
       - name: Set up Docker Buildx

.github/workflows/build-push-latest-nixos-arion.yaml

@@ -22,7 +22,7 @@ jobs:
   test:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
+      - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       - name: Set up QEMU
         uses: docker/setup-qemu-action@v3
       - name: Set up Docker Buildx
@@ -94,7 +94,7 @@ jobs:
     needs:
       - test
     steps:
-      - uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
+      - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       - name: Set up QEMU
         uses: docker/setup-qemu-action@v3
       - name: Set up Docker Buildx

.github/workflows/build-push-latest-nixos.yaml

@@ -37,7 +37,7 @@ jobs:
             home_manager_version_string: "master"
             default_tag: false
     steps:
-      - uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
+      - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
 
       - name: Set up PATH for NixOS (self-hosted)
         if: matrix.nix_system == 'aarch64-linux'
@@ -116,7 +116,7 @@ jobs:
     needs:
       - nix-build
     steps:
-      - uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
+      - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
 
       - name: Login to Registry
         uses: docker/login-action@v3

.github/workflows/build-push-latest.yaml

@@ -37,7 +37,7 @@ jobs:
             home_manager_channel: "https://github.com/nix-community/home-manager/archive/release-25.11.tar.gz"
             default_tag: true
     steps:
-      - uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
+      - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
       - name: Set up QEMU
         uses: docker/setup-qemu-action@v3
       - name: Set up Docker Buildx

.github/workflows/release.yaml

@@ -7,7 +7,7 @@ jobs:
     # if: ${{ github.ref == 'refs/heads/main' }}
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
+      - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
 
       - name: "Set namespace"
         id: set-namespace

.github/workflows/test-pr.yaml

@@ -25,7 +25,7 @@ jobs:
       matrix:
         templates: ${{ fromJSON(needs.detect-changes.outputs.templates) }}
     steps:
-      - uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
+      - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
 
       - name: Smoke test for '${{ matrix.templates }}'
         id: smoke_test