ci: update actions/checkout action to v5 (#66)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

.github/workflows/test.yaml

@@ -31,7 +31,7 @@ jobs:
         go_version: ["~1.20", "~1.21", "~1.22", "~1.23", "~1.24"]
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v5
 
       - name: Install Go
         uses: actions/setup-go@v5