sanity.conf: Update minimum bitbake version to 2.12.1

Needed for multiprocessing module in bb used in the next commit.

It was added to bitbake in 62be9113d98fccb347c6aa0a10d5c4ee2857f8b6
which was backported to 2.12 branch and tagged as 2.12.1

(From OE-Core rev: fcfc3056b0b8d0c63fddd0a7624622aee9a1c2f1)

Signed-off-by: Martin Jansa <martin.jansa@gmail.com>
Signed-off-by: Steve Sakoman <steve@sakoman.com>

meta/conf/sanity.conf

@@ -3,7 +3,7 @@
 # See sanity.bbclass
 #
 # Expert users can confirm their sanity with "touch conf/sanity.conf"
-BB_MIN_VERSION = "2.12.0"
+BB_MIN_VERSION = "2.12.1"
 
 SANITY_ABIFILE = "${TMPDIR}/abi_version"