Bump actions/checkout from 4 to 6

Bumps [actions/checkout](https://github.com/actions/checkout) from 4 to 6.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v4...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] <support@github.com>

Author: dependabot[bot]

.github/workflows/auto-merge-upstream-manual-approval-gate.yaml

@@ -13,7 +13,7 @@ jobs:
       pull-requests: write
     steps:
     - name: Checkout the current repo
-      uses: actions/checkout@v4
+      uses: actions/checkout@v6
     - name: auto-merge-upstream-manual-approval-gate
       run: |
         gh auth status

.github/workflows/latest.yml

@@ -12,7 +12,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v6
     - name: Set up Go
       uses: actions/setup-go@v5
       with:
@@ -43,7 +43,7 @@ jobs:
       with:
         go-version: 1.21
     - uses: imjasonh/setup-ko@v0.9
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v6
     - uses: actions/cache@v4
       with:
         path: |
@@ -72,7 +72,7 @@ jobs:
     - uses: actions/setup-go@v5
       with:
         go-version: 1.21
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v6
     - uses: actions/cache@v4
       with:
         path: |

.github/workflows/release.yml

@@ -18,7 +18,7 @@ jobs:
       repository-projects: write
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - uses: docker/login-action@v3
         with:
           registry: ghcr.io

.github/workflows/update-sources-manual-approval-gate.yaml

@@ -15,7 +15,7 @@ jobs:
       pull-requests: write
     steps:
     - name: Checkout the current repo
-      uses: actions/checkout@v4
+      uses: actions/checkout@v6
       with:
         ref: main