CI: split files into chunks of 2GBs which is the maximum limit for release files

.github/workflows/CI.yml

@@ -14,11 +14,11 @@ jobs:
       run: |
         for iso in $(nix flake show --json | nix run nixpkgs#jq -- -r keys[]); do
           nix build .#$iso
-          cp result/iso/*.iso $iso.iso
+          split -d result/iso/*.iso -b 2G $iso.iso-part-
           rm result
         done
     - name: Release
       uses: softprops/action-gh-release@v1
       if: startsWith(github.ref, 'refs/tags/v') && contains(github.ref, '.')
       with:
-        files: "*.iso"
+        files: "*.iso-part-*"