go.mod: update wireguard-go commit.
@@ -19,7 +19,7 @@ require (
github.com/peterbourgon/ff/v2 v2.0.0
github.com/tailscale/hujson v0.0.0-20190930033718-5098e564d9b3 // indirect
github.com/tailscale/winipcfg-go v0.0.0-20200213045944-185b07f8233f
- github.com/tailscale/wireguard-go v0.0.0-20200301171525-c79fb046ceee
+ github.com/tailscale/wireguard-go v0.0.0-20200301215411-6dde709dd694
golang.org/x/crypto v0.0.0-20200221231518-2aa609cf4a9d
golang.org/x/net v0.0.0-20200301022130-244492dfa37a // indirect
golang.org/x/oauth2 v0.0.0-20200107190931-bf48bf16ab8d
