security/lego: Unbreak on aarch64

> Building lego from ./cmd/lego

golang.org/x/sys/unix

vendor/golang.org/x/sys/unix/ztypes_freebsd_arm64.go:400:12: undefined: uint128

http://thunderx1.nyi.freebsd.org/data/head-arm64-default/p518685_s355218/logs/errors/lego-3.2.0.log

Unbreak by updating golang.org/x/sys to 33540a1f6037 and golang.org/x/net to
83d349e8ac1a which adds support for freebsd/arm64.

PR: 242581
Approved by: Matthew Horan <matt@matthoran.com> (maintainer)