CI: minor: actions/checkout from 4 to 5

Author: kataras

.github/workflows/ci.yml

@@ -21,7 +21,7 @@ jobs:
     steps:
 
     - name: Check out code into the Go module directory
-      uses: actions/checkout@v4
+      uses: actions/checkout@v5
 
     - name: Set up Go 1.x
       uses: actions/setup-go@v5