Add Nonguix channel, increase output image size

.github/workflows/build.yaml

@@ -21,8 +21,20 @@ jobs:
 
       - name: Install Guix
         uses: PromyLOPh/guix-install-action@v1
+        with:
+          channels: |
+            (cons* (channel
+                    (name 'nonguix)
+                    (url "https://gitlab.com/nonguix/nonguix")
+                    ;; Enable signature verification:
+                    (introduction
+                     (make-channel-introduction
+                      "897c1a470da759236cc11798f4e0a5f7d4d59fbc"
+                      (openpgp-fingerprint
+                        "2A39 3FFF 68F4 EF7A 3D29  12AF 6F51 20A0 22FB B2D5"))))
+                    %default-channels)
 
       - name: Build ISO
         run: |
           #$image=$(guix system image installer.scm)
-          guix system image installer.scm
+          guix system image installer.scm --image-size=5G