Manifest version 2 is deprecated, and support will be removed in 2023

[nelsonni]

Describe the bug
When compiling Synectic, the following warning is throw:

(node:4987) ExtensionLoadWarning: Warnings loading extension at /Users/nelsonni/Library/Application Support/Synectic/extensions/lmhkpmbekcpmknklioeibfkpmmfibljd:
  Manifest version 2 is deprecated, and support will be removed in 2023. See https://developer.chrome.com/blog/mv2-transition/ for more details.
  Permission 'notifications' is unknown or URL pattern is malformed.
  Permission 'contextMenus' is unknown or URL pattern is malformed.

(Use `Electron --trace-warnings ...` to show where the warning was created)
Added extension: Redux DevTools

This message is passed through from the Redux DevTools plugin. Relevant issues being tracked for resolution:

• Upgrade to Manifest V3 reduxjs/redux-devtools#1037
• [DevTools Bug]: Electron support broken in 4.27 facebook/react#25843
• [DevTools] Manifest version 2 is deprecated facebook/react#24522
• [Bug]: Failed to load React Devtools electron/electron#36545
• Failed to load REACT_DEVELOPER_TOOLS with "allowFileAccess: true". MarshallOfSound/electron-devtools-installer#232
• React dev tools fail to work electron-react-boilerplate/electron-react-boilerplate#3419
• update to prevent deprecated, soon to be removed dev tools electron-react-boilerplate/electron-react-boilerplate#3407

Expected behavior
Compiled without warnings.

Versions (please complete the following information):

• OS: MacOS, Windows, Linux
• Synectic Version: 3.2.0