Cache the changelog on onboarding page

[mdolr]

trafficstars

Currently every time you open the onboarding / settings page via the popup it requests the changelog using the Github API. The request is done js/utils/onBoardingbootstrap.js. The response should be cached as the extension likely won't update while its running.

(don't ask if you can work on this please :pray:, I wouldn't have created the issue otherwise)

[ask-imran]

Picking it up

[joelazwar]

hey @mdolr since I saw this wasn't fixed yet, made a quick PR for this issue, #156