tailscale/version/distro
Andrew Lytvynov 306deea03a
cmd/tailscale/cli,version/distro: update support for Alpine ()
Similar to Arch support, use the latest version info from the official
`apk` repo and don't offer explicit track or version switching.
Add detection for Alpine Linux in version/distro along the way.

Updates 

Signed-off-by: Andrew Lytvynov <awly@tailscale.com>
..
distro.go cmd/tailscale/cli,version/distro: update support for Alpine ()
distro_test.go all: update copyright and license headers