docs(GUI): minimim macOS supported platform (#765)
docs(GUI): minimim macOS supported platform (#765)

Since the Etcher GUI is based on Electron, it only runs on platforms
supported by Electron, which in the case of macOS, is 10.9 and newer
versions.

As an alternative, we propose using the Etcher CLI.

See: https://github.com/electron/electron/blob/master/docs/tutorial/supported-platforms.md
Fixes: https://github.com/resin-io/etcher/issues/761
Signed-off-by: Juan Cruz Viotti <4148f5869aa1bcd7efd85b513a5874967e585032@openmailbox.org>
resin-io/resin-etcher,resin-io/etcher,resin-io/etcher,resin-io/etcher,resin-io/resin-etcher,resin-io/etcher,resin-io/herostratus,resin-io/herostratus,resin-io/etcher