Only use nvmrc in github actions build pipeline

[stickyPiston]

Currently we still use the setup-node action, but we also use nvm in the github actions build. If we use nvm in the build pipeline, then we only need to change the .nvmrc file to update the used node.js version.

[pranjalarora98]

@stickyPiston can you plz assign this issue to me? I wud like to work on it..thanjs

[SilasPeters]

Hi there! I deleted your other comment because it looks like a bot. If you just create a PR then that will be enough! This issue won't run away nor will be assigned to anyone soon.