chore: bump electron version to 12.0.6

* Bump electron version to 12.0.6
* Move web content clean up logic to window close event

Reference from electron release notes:
> Fixed the window-all-closed event being emitted while the last
BrowserWindow was still in the process of being closed.

package-lock.json

@@ -7290,9 +7290,9 @@
       }
     },
     "electron": {
-      "version": "12.0.5",
-      "resolved": "https://registry.npmjs.org/electron/-/electron-12.0.5.tgz",
-      "integrity": "sha512-z0xYB3sPr0qZcDrHUUWqooPKe3yUzBDxQcgQe3f2TLstA84JIFXBoaIJCPh/fJW0+JdF/ZFVeK2SNgLhYtRV+Q==",
+      "version": "12.0.6",
+      "resolved": "https://registry.npmjs.org/electron/-/electron-12.0.6.tgz",
+      "integrity": "sha512-+fqhpdG6Fd6LzsizMdaSPC1I8tfsMT8/7fsYBgABED3hEWdus/rt6CQ54P3/EWZyQebtyHR6HXtlofUqKMV3KQ==",
       "dev": true,
       "requires": {
         "@electron/get": "^1.0.1",

package.json

@@ -70,7 +70,7 @@
     "copy-webpack-plugin": "8.0.0",
     "css-loader": "^5.1.1",
     "devtron": "^1.4.0",
-    "electron": "^12.0.5",
+    "electron": "^12.0.6",
     "electron-builder": "^22.10.5",
     "electron-builder-squirrel-windows": "^22.10.5",
     "electron-debug": "^3.2.0",

src/main/index.js

@@ -326,6 +326,22 @@ function runApp() {
       newWindow.focus()
     })
 
+    newWindow.on('close', () => {
+      newWindow.webContents.session.clearCache()
+      newWindow.webContents.session.clearStorageData({
+        storages: [
+          'appcache',
+          'cookies',
+          'filesystem',
+          'indexdb',
+          'shadercache',
+          'websql',
+          'serviceworkers',
+          'cachestorage'
+        ]
+      })
+    })
+
     newWindow.on('closed', () => {
       // Remove closed window
       openedWindows = openedWindows.filter((window) => window !== newWindow)
@@ -406,20 +422,6 @@ function runApp() {
     if (process.platform !== 'darwin') {
       app.quit()
     }
-
-    mainWindow.webContents.session.clearCache()
-    mainWindow.webContents.session.clearStorageData({
-      storages: [
-        'appcache',
-        'cookies',
-        'filesystem',
-        'indexdb',
-        'shadercache',
-        'websql',
-        'serviceworkers',
-        'cachestorage'
-      ]
-    })
   })
 
   app.on('activate', () => {