Update actions/checkout action to v7 (#301)

Author: renovate[bot]

.github/workflows/artifacts.yml

@@ -18,7 +18,7 @@ jobs:
       packages: write
 
     steps:
-    - uses: actions/checkout@v6
+    - uses: actions/checkout@v7
       with:
         fetch-depth: 0
     - uses: docker/login-action@v4

.github/workflows/verify.yml

@@ -13,7 +13,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v6
+    - uses: actions/checkout@v7
     - uses: actions/setup-go@v6
       with:
         go-version: 1.26.4