go.mod: bump go4.org/unsafe/assume-no-moving-gc for Go 1.19beta1

Otherwise we crash at startup with Go 1.19beta1.

Updates #4872

Change-Id: I371df4146735f7e066efd2edd48c1a305906c13d
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