use multiple runners for the multi-arch build

.gitea/workflows/ci.yml

@@ -109,7 +109,7 @@ jobs:
           digest="${{ steps.build.outputs.digest }}"
           touch "${{ runner.temp }}/digests/${digest#sha256:}"
       - name: Upload digest
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@v3
         with:
           name: digests-${{ env.PLATFORM_PAIR }}
           path: ${{ runner.temp }}/digests/*
@@ -121,7 +121,7 @@ jobs:
       - build
     steps:
       - name: Download digests
-        uses: actions/download-artifact@v4
+        uses: actions/download-artifact@v3
         with:
           path: ${{ runner.temp }}/digests
           pattern: digests-*