Update link of electron-supported-platforms in README.md

[PeterDaveHello]

This doc has moved for a while ;)

[PeterDaveHello]

@Lizzieepton not sure if you can help review and merge this?

[dfunckt]

Hey @PeterDaveHello -- thanks for the PR. Etcher is currently stuck at an older Electron version so links to their docs for the supported platforms are misleading -- for example, we currently do not provide Apple Silicon builds, despite what their docs says. I'd much rather you deleted the complete Note: about supported platforms and the link -- the list of actually supported platforms is provided just above that note.

[dfunckt]

BTW, make sure to provide a Change-type with your commit message so that the PR becomes mergeable. For example, here is how to format a commit message that is acceptable by our CI:

Updated foo with bar

Change-type: patch

[dfunckt]

Superseded by #4132

[PeterDaveHello]

Oh, sorry that I didn't notice and revise on time, but it's good to see some updates here.