update GitHub actions/checkout to v5

.github/workflows/test.yml

@@ -12,7 +12,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v5
     - name: clone mkiocccentry
       run: git clone https://github.com/ioccc-src/mkiocccentry
     - name: install jparse