go.mod: update netstack

Fixes a atomic alignment crash on 32-bit machines.

Fixes #2129
Fixes tailscale/tailscale-synology#66 (same)

Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
This commit is contained in:
Internal Server Error - Gitea: Git with a cup of tea
500 Internal Server Error

Gitea Version: 1.28.0+dev-477-g8b6ad49a5f