go.mod: update to new wireguard-go version.

Signed-off-by: David Anderson <danderson@tailscale.com>

go.mod

@@ -24,7 +24,7 @@ require (
 	github.com/peterbourgon/ff/v2 v2.0.0
 	github.com/pkg/errors v0.9.1 // indirect
 	github.com/tailscale/depaware v0.0.0-20201214215404-77d1e9757027
-	github.com/tailscale/wireguard-go v0.0.0-20210324165952-2963b66bc23a
+	github.com/tailscale/wireguard-go v0.0.0-20210327173134-f6a42a1646a0
 	github.com/tcnksm/go-httpstat v0.2.0
 	github.com/toqueteos/webbrowser v1.2.0
 	go4.org/mem v0.0.0-20201119185036-c04c5a6ff174

go.sum

@@ -121,6 +121,8 @@ github.com/tailscale/wireguard-go v0.0.0-20210210202228-3cc76ed5f222 h1:VzTS7LIw
 github.com/tailscale/wireguard-go v0.0.0-20210210202228-3cc76ed5f222/go.mod h1:6t0OVdJwFOKFnvaHaVMKG6GznWaHqkmiR2n3kH0t924=
 github.com/tailscale/wireguard-go v0.0.0-20210324165952-2963b66bc23a h1:tQ7Y0ALSe5109GMFB7TVtfNBsVcAuM422hVSJrXWMTE=
 github.com/tailscale/wireguard-go v0.0.0-20210324165952-2963b66bc23a/go.mod h1:6t0OVdJwFOKFnvaHaVMKG6GznWaHqkmiR2n3kH0t924=
+github.com/tailscale/wireguard-go v0.0.0-20210327173134-f6a42a1646a0 h1:7KFBvUmm3TW/K+bAN22D7M6xSSoY/39s+PajaNBGrLw=
+github.com/tailscale/wireguard-go v0.0.0-20210327173134-f6a42a1646a0/go.mod h1:6t0OVdJwFOKFnvaHaVMKG6GznWaHqkmiR2n3kH0t924=
 github.com/tcnksm/go-httpstat v0.2.0 h1:rP7T5e5U2HfmOBmZzGgGZjBQ5/GluWUylujl0tJ04I0=
 github.com/tcnksm/go-httpstat v0.2.0/go.mod h1:s3JVJFtQxtBEBC9dwcdTTXS9xFnM3SXAZwPG41aurT8=
 github.com/toqueteos/webbrowser v1.2.0 h1:tVP/gpK69Fx+qMJKsLE7TD8LuGWPnEV71wBN9rrstGQ=