Update actions/checkout action to v6

.github/workflows/ci.yml

@@ -15,11 +15,11 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Check out code
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
       - name: Set up Go
         uses: actions/setup-go@v6
         with:
-          go-version: "1.25.5"
+          go-version: "1.25.4"
       - name: Cache Go modules
         uses: actions/cache@v4
         with:
@@ -47,13 +47,13 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Check out code
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
       - name: Set up Go
         uses: actions/setup-go@v6
         with:
-          go-version: "1.25.5"
+          go-version: "1.25.4"
       - name: Run golangci-lint
-        uses: golangci/golangci-lint-action@v9
+        uses: golangci/golangci-lint-action@v8
         with:
           version: latest
           args: --timeout=5m