doc: update supported version of FreeBSD to 12.4

Refs: nodejs/build#3134
PR-URL: #47838
Reviewed-By: Tobias Nießen <tniessen@tnie.de>
Reviewed-By: Moshe Atlow <moshe@atlow.co.il>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>

BUILDING.md

@@ -118,7 +118,7 @@ platforms. This is true regardless of entries in the table below.
 | macOS            | arm64            | >= 11                             | Tier 1                                          |                                      |
 | SmartOS          | x64              | >= 18                             | Tier 2                                          |                                      |
 | AIX              | ppc64be >=power8 | >= 7.2 TL04                       | Tier 2                                          |                                      |
-| FreeBSD          | x64              | >= 12.2                           | Experimental                                    |                                      |
+| FreeBSD          | x64              | >= 12.4                           | Experimental                                    |                                      |
 
 [^1]: Older kernel versions may work. However official Node.js release
     binaries are [built on RHEL 8 systems](#official-binary-platforms-and-toolchains)