bump actions/checkout@v4 (#113)

Author: shogo82148

.github/workflows/test.yml

@@ -5,7 +5,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Check out code
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Install Go
         uses: actions/setup-go@v5
@@ -36,7 +36,7 @@ jobs:
           go-version: ${{ matrix.go-version }}
 
       - name: Check out code
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
 
       - name: Test
         run: go test -race ./...