[ecashaddrjs] Fixing dependency tree

Summary:
T2848

Depends on D13387

npm audit brought up a number of moderate to severe issues. Resolved with a combination of

• npm audit fix
• individually updating dev dependencies to latest version
• removing coveralls and its associated .yaml file, which had no fix, no new version in 2 years, not used here
• Update unit tests to use updated syntax of latest random-js version

Test Plan:
npm audit and all good
npm test and unit tests pass
npm run build and no build errors

Reviewers: #bitcoin_abc, Fabien

Reviewed By: #bitcoin_abc, Fabien

Subscribers: Fabien

Differential Revision: https://reviews.bitcoinabc.org/D13388