Update electron to version 30.1.2

[tsmaeder]

What it does

Fixes #14014

Contributed on behalf of STMicroelectronics

How to test

Make sure everything builds and test general functionality in the electron example. Make sure there are no new error messages in the log

Follow-ups

Review checklist

• As an author, I have thoroughly tested my changes and carefully followed the review guidelines

Reminder for reviewers

• As a reviewer, I agree to behave in accordance with the review guidelines

[tsmaeder]

Draft PR while we wait for IP-Ticket approval

[planger]

Thank you @tsmaeder! Works like a charm!

I tested

• opening Electron Theia
• Keyboard shortcuts
• Application menus
• Context menu
• Opening a new instance via Welcome screen
• Native dialogs via Save File dialog and Open Folder dialog

I noticed two issues (see below), however, I could reproduce both with master, so they are not caused by the Electron update.

Unrelated observed issues

Secondary window didn't close:

1. Extract text editor into secondary window
2. Make changes
3. Close window and select "Don't save"
4. Window stays open and is empty, cannot be closed

In the console I get the following error:

(node:133669) UnhandledPromiseRejectionWarning: Error: Cancelled
    at cancelled (/home/philip/Git/OpenSource/Theia/theia/examples/electron/lib/backend/packages_core_lib_common_index_js-node_modules_vscode-languageserver-types_lib_umd_sync_recursive.js:427:12)
    at /home/philip/Git/OpenSource/Theia/theia/examples/electron/lib/backend/packages_core_lib_common_index_js-node_modules_vscode-languageserver-types_lib_umd_sync_recursive.js:5570:54
    at /home/philip/Git/OpenSource/Theia/theia/examples/electron/lib/backend/packages_core_lib_common_index_js-node_modules_vscode-languageserver-types_lib_umd_sync_recursive.js:1410:69
    at CallbackList.invoke (/home/philip/Git/OpenSource/Theia/theia/examples/electron/lib/backend/packages_core_lib_common_index_js-node_modules_vscode-languageserver-types_lib_umd_sync_recursive.js:1416:26)
    at Emitter.fire (/home/philip/Git/OpenSource/Theia/theia/examples/electron/lib/backend/packages_core_lib_common_index_js-node_modules_vscode-languageserver-types_lib_umd_sync_recursive.js:1531:36)
    at MutableToken.cancel (/home/philip/Git/OpenSource/Theia/theia/examples/electron/lib/backend/packages_core_lib_common_index_js-node_modules_vscode-languageserver-types_lib_umd_sync_recursive.js:362:31)
    at CancellationTokenSource.cancel (/home/philip/Git/OpenSource/Theia/theia/examples/electron/lib/backend/packages_core_lib_common_index_js-node_modules_vscode-languageserver-types_lib_umd_sync_recursive.js:407:25)
    at showWindowAndCloseSplashScreen (/home/philip/Git/OpenSource/Theia/theia/examples/electron/lib/backend/electron-main.js:1393:31)
    at /home/philip/Git/OpenSource/Theia/theia/examples/electron/lib/backend/electron-main.js:1401:36
(Use `electron --trace-warnings ...` to show where the warning was created)
(node:133669) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). To terminate the node process on unhandled promise rejection, use the CLI flag `--unhandled-rejections=strict` (see https://nodejs.org/api/cli.html#cli_unhandled_rejections_mode). (rejection id: 2)