Specify universal mac app as targets for electon-builder (#338)

* Specify universal mac app as targets for electon-builder

* Add x64ArchFiles rule

Author: jtklein

package.json

@@ -153,6 +153,22 @@
       "sign": false
     },
     "mac": {
+      "mergeASARs": false,
+      "target": [
+        {
+          "target": "dmg",
+          "arch": [
+            "universal"
+          ]
+        },
+        {
+          "target": "zip",
+          "arch": [
+            "universal"
+          ]
+        }
+      ],
+      "x64ArchFiles": "**/static/bin/*",
       "category": "public.app-category.education",
       "hardenedRuntime": true,
       "entitlements": "public/entitlements.mac.inherit.plist",