[appimage] Fix: DNS-Konfiguration für DinD-Container

- Container-Options: --dns 8.8.8.8 --dns 1.1.1.1
- Fallback-Step: /etc/resolv.conf ergänzen
- Löst "Could not resolve host" im Forgejo Runner

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

.forgejo/workflows/build-appimage.yml

@@ -16,8 +16,15 @@ jobs:
     if: contains(github.event.head_commit.message, '[appimage]') || startsWith(github.ref, 'refs/tags/v')
     container:
       image: rust:1.83-bookworm
+      options: --dns 8.8.8.8 --dns 1.1.1.1
 
     steps:
+      - name: Configure DNS Fallback
+        run: |
+          # DNS-Fix für DinD-Umgebung
+          echo "nameserver 8.8.8.8" >> /etc/resolv.conf
+          echo "nameserver 1.1.1.1" >> /etc/resolv.conf
+
       - name: Checkout
         run: |
           git clone --depth 1 --branch "${GITHUB_REF_NAME}" \