Remove `wait-on` from devDep

[cheehongw]

wait-on is a cross-platform CLI utility to wait for files to be available.

There are 2 ways to use this library:

1. directly in the CLI

   • The command wait-on doesn't appear to be used at all in this project.
   • The command wait-on is not used in package.json scripts
   • None of the packages use wait-on as a dev-dep (verified using npm ls wait-on)

2. Via the node.js programmatic API

   • a check using npm-check suggests that this is not used anywhere in code
   • wait-on is not imported anywhere based on a ctrl-f search on the repository

See: https://www.npmjs.com/package/wait-on#usage

From git blame, it appears that this library was included when this project was initialized in #1 and when electron was used.