chore(deps): bump actions/checkout from 5 to 6 (#934)

Bumps [actions/checkout](https://github.com/actions/checkout) from 5 to 6.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v5...v6)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

.github/workflows/pages.yml

@@ -13,7 +13,7 @@ jobs:
     env:
       SSH_AUTH_SOCK: /tmp/ssh_agent.sock
     steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
     - uses: cachix/install-nix-action@v31
     - uses: cachix/cachix-action@v16
       with:

.github/workflows/publish-flakehub.yml

@@ -11,7 +11,7 @@ jobs:
       id-token: "write"
       contents: "read"
     steps:
-      - uses: "actions/checkout@v5"
+      - uses: "actions/checkout@v6"
       - uses: "DeterminateSystems/nix-installer-action@main"
       - uses: "DeterminateSystems/flakehub-push@main"
         with:

.github/workflows/test.yml

@@ -36,7 +36,7 @@ jobs:
             nixpkgs-override: "--override-input nixpkgs $(./ci/ref-from-lock.sh ./test#nixpkgs-latest-release)"
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
     - uses: cachix/install-nix-action@v31
       with:
         install_url: ${{ matrix.install_url }}
@@ -70,7 +70,7 @@ jobs:
           - trunk
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
     - uses: cachix/install-nix-action@v31
     - uses: cachix/cachix-action@v16
       with:
@@ -90,7 +90,7 @@ jobs:
       fail-fast: false
     runs-on: macos-latest
     steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
     - uses: cachix/install-nix-action@v31
     - uses: cachix/cachix-action@v16
       with:
@@ -119,7 +119,7 @@ jobs:
   lints:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
     - uses: cachix/install-nix-action@v31
     - name: check formatting
       run: nix fmt -- --ci

.github/workflows/update-flake.yml

@@ -12,7 +12,7 @@ jobs:
   update-and-push-deps:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
     - uses: cachix/install-nix-action@v31
       with:
         extra_nix_config: |