CI: handle build matrix separately

.github/workflows/build.yml

@@ -41,6 +41,32 @@ jobs:
         shell: bash
         run: nix build .#images.${{ matrix.image }} -o ${{ matrix.image }} --print-build-logs
 
+      - uses: actions/upload-artifact@v4
+        with:
+          name: ${{ matrix.image }}-iso-image
+          path: ${{ matrix.image }}/iso/*.iso
+
+  # publish built images
+  publish-images:
+    name: "Build ISO Images"
+    runs-on: ubuntu-latest
+    needs: build-images
+
+    permissions:
+      contents: write
+
+    env:
+      GITHUB_TOKEN: "${{ secrets.GITHUB_TOKEN }}"
+
+    steps:
+      - name: Download ISO Artifacts
+        uses: actions/download-artifact@v4
+        with:
+          merge-multiple: true
+
+      - name: Display structure of downloaded files
+        run: ls -R
+
       - name: Get current date
         id: get-date
         # output format: 2023-12-30-234559
@@ -52,10 +78,7 @@ jobs:
         with:
           name: "${{ steps.get-date.outputs.date }}"
           tag_name: "${{ steps.get-date.outputs.date }}"
-          files: |
-            erebus/iso/*.iso
-            gaea/iso/*.iso
-
+          files: "*.iso"
           body: |
             # Weekly Iso Releases
 
@@ -81,6 +104,3 @@ jobs:
 
             Do note that those configurations make assumptions about your setup, and may yield undesirable systems. Use
             at your own risk.
-
-        env:
-          GITHUB_TOKEN: "${{ secrets.GITHUB_TOKEN }}"