fix ci: add checkout to release job so gh has git context

Author: MochiOS Team

.github/workflows/build-iso.yml

@@ -72,6 +72,7 @@ jobs:
     permissions:
       contents: write
     steps:
+      - uses: actions/checkout@v4
       - uses: actions/download-artifact@v7
         with:
           name: mochios-iso