Bump actions/checkout from 3 to 4

Dependabot couldn't find the original pull request head commit, 3dc972f.

Author: dependabot[bot]

.github/workflows/ci.yml

@@ -17,7 +17,7 @@ jobs:
     runs-on: ${{ matrix.platform }}
     steps:
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
         with:
           fetch-depth: 0
       - name: Set up Go
@@ -39,7 +39,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Check out code
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       - name: goreleaser
         if: success()
         uses: docker://goreleaser/goreleaser:latest
@@ -58,7 +58,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Check out code
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       - name: Set up QEMU
         uses: docker/setup-qemu-action@v2
       - name: Set up Docker Buildx