tls: add --tls-min-v1.2 CLI switch

Switch added in v11.x, add it to master/12.x for consistency and
compatibility.

See: https://github.com/nodejs/node/pull/26951, commit bf2c2835

PR-URL: https://github.com/nodejs/node/pull/27520


Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>
Reviewed-By: Сковорода Никита Андреевич <chalkerx@gmail.com>