git: 6f49f5cdde1c..23aff1240891 - vendor/bc - vendor branch updated

From: Stefan Eßer <se_at_FreeBSD.org>
Date: Tue, 30 Nov 2021 17:31:36 UTC
The branch vendor/bc has been updated by se:

URL: https://cgit.FreeBSD.org/src/log/?id=6f49f5cdde1c..23aff1240891

23aff1240891 vendor/bc: import release 5.2.0