Fyne v2.8 lands, sync/atomic gets Max and Min

Fyne v2.8 is out, with over a thousand commits from 39 contributors bringing new graphics, APIs and speedups to the cross-platform toolkit. On the proposal side, sync/atomic is picking up Max and Min operators (prompted by a TODO in the runtime sweeper, which is a satisfying way for a proposal to start life), Transport.CancelRequest is finally being dropped after years of deprecation, and the x/tools crew are standardising how -help works across the project's command-line tools. Elsewhere, a write-up on Go value objects makes the case that the extra types pay for themselves in bugs that never happen.