bitbake: bitbake: enable python warnings at the first opportunity

We really do want to see those, as they tend to turn into
hard errors eventually, as what happened with collections
vs collections.abc in python 3.10.

(Bitbake rev: bc43fbb86361a21dc2d5deb910810c5a77fdabe8)

Signed-off-by: Alexander Kanavin <alex@linutronix.de>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

bitbake/bin/bitbake-diffsigs

@@ -11,6 +11,7 @@
 import os
 import sys
 import warnings
+warnings.simplefilter("default")
 import argparse
 import logging
 import pickle