build(electron): add flatpak config

forge.config.cjs

@@ -59,6 +59,15 @@ module.exports = {
                 }
             }
         },
+        {
+            name: "@electron-forge/maker-flatpak",
+            config: {
+                options: {
+                    icon: "./images/app-icons/png/128x128.png",
+                    desktopTemplate: path.resolve("./bin/electron-forge/desktop.ejs"),
+                },
+            }
+        },
         {
             name: "@electron-forge/maker-rpm",
             config: {