[202012][sonic-platform-common] submodule update

Following commits will be added

8bfe9c0 (HEAD -> 202012, origin/202012) [Credo][Ycable] improve logging
for Server Powered off/Faulty cables (sonic-net#272)

Signed-off-by: vaibhav-dahiya <[email protected]>

Author: vdahiya12