go.mod: bump netstack for clone reset fix (#4379)

In tracking down issue #4144 and reading through the netstack code in
detail, I discovered that the packet buf Clone path did not reset the
packetbuf it was getting from the sync.Pool. The fix was sent upstream
https://github.com/google/gvisor/pull/7385, and this bump pulls that in.
At this time there is no known path that this fixes, however at the time
of upstream submission this reset at least one field that could lead to
incorrect packet routing if exercised, a situation that could therefore
lead to an information leak.

Signed-off-by: James Tucker <james@tailscale.com>

cmd/tailscaled/depaware.txt

@@ -131,7 +131,7 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
         gvisor.dev/gvisor/pkg/log                                    from gvisor.dev/gvisor/pkg/context+
         gvisor.dev/gvisor/pkg/rand                                   from gvisor.dev/gvisor/pkg/tcpip/network/hash+
         gvisor.dev/gvisor/pkg/refs                                   from gvisor.dev/gvisor/pkg/refsvfs2+
-        gvisor.dev/gvisor/pkg/refsvfs2                               from gvisor.dev/gvisor/pkg/tcpip/stack
+        gvisor.dev/gvisor/pkg/refsvfs2                               from gvisor.dev/gvisor/pkg/tcpip/stack+
      💣 gvisor.dev/gvisor/pkg/sleep                                  from gvisor.dev/gvisor/pkg/tcpip/transport/tcp
      💣 gvisor.dev/gvisor/pkg/state                                  from gvisor.dev/gvisor/pkg/atomicbitops+
         gvisor.dev/gvisor/pkg/state/wire                             from gvisor.dev/gvisor/pkg/state

go.mod

@@ -57,7 +57,7 @@ require (
 	golang.org/x/tools v0.1.11-0.20220316014157-77aa08bb151a
 	golang.zx2c4.com/wireguard v0.0.0-20220317000134-95b48cdb3961
 	golang.zx2c4.com/wireguard/windows v0.4.10
-	gvisor.dev/gvisor v0.0.0-20220318082524-536b85ae1a6a
+	gvisor.dev/gvisor v0.0.0-20220407223209-21871174d445
 	honnef.co/go/tools v0.4.0-0.dev.0.20220404092545-59d7a2877f83
 	inet.af/netaddr v0.0.0-20211027220019-c74959edd3b6
 	inet.af/peercred v0.0.0-20210906144145-0893ea02156a

go.sum

@@ -1833,8 +1833,8 @@ gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C
 gopkg.in/yaml.v3 v3.0.0-20200615113413-eeeca48fe776/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 gopkg.in/yaml.v3 v3.0.0-20210107192922-496545a6307b h1:h8qDotaEPuJATrMmW04NCwg7v22aHH28wwpauUhK9Oo=
 gopkg.in/yaml.v3 v3.0.0-20210107192922-496545a6307b/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
-gvisor.dev/gvisor v0.0.0-20220318082524-536b85ae1a6a h1:sQAuNyyy59GRxS8npo8nyOr5yM46gB7QzVFiq6yvHdg=
-gvisor.dev/gvisor v0.0.0-20220318082524-536b85ae1a6a/go.mod h1:tWwEcFvJavs154OdjFCw78axNrsDlz4Zh8jvPqwcpGI=
+gvisor.dev/gvisor v0.0.0-20220407223209-21871174d445 h1:pLNQCtMzh4O6rdhoUeWHuutt4yMft+B9Cgw/bezWchE=
+gvisor.dev/gvisor v0.0.0-20220407223209-21871174d445/go.mod h1:tWwEcFvJavs154OdjFCw78axNrsDlz4Zh8jvPqwcpGI=
 honnef.co/go/tools v0.0.0-20190102054323-c2f93a96b099/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=
 honnef.co/go/tools v0.0.0-20190106161140-3f1c8253044a/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=
 honnef.co/go/tools v0.0.0-20190418001031-e561f6794a2a/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=