CI: Switch to actions/downlaod-artifact@v4

v2 is not supported anymore by Github's CI.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>

Author: pcercuei

.github/workflows/main.yml

@@ -146,7 +146,7 @@ jobs:
       with:
         repository: 'OpenDingux/odbootd'
         path: 'odbootd'
-    - uses: actions/download-artifact@v2
+    - uses: actions/download-artifact@v4
       with:
         name: vmlinuz
         path: odbootd