ci: upgrade GitHub Actions for Node 24 (#3)

Author: Pigbibi

.github/workflows/validate.yml

@@ -8,8 +8,8 @@ jobs:
   validate:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
-      - uses: actions/setup-python@v5
+      - uses: actions/checkout@v6
+      - uses: actions/setup-python@v6
         with:
           python-version: "3.12"
       - name: Validate runtime targets