[sonic-platform-common] submodule update

ef4b3ec [Y-Cable] add the definition inside setup.py to include sonic_y_cable.credo as a package (sonic-net#211)
7d81488 [Y-Cable][Credo] Credo implementation of YCable class which inherits from YCableBase required for Y-Cable API's in sonic-platform-daemons (sonic-net#203)
3efb093 [sonic_y_cable] add abstract class YCableBase required for Y-cable API support for multiple vendors (sonic-net#186)

Signed-off-by: vaibhav-dahiya <vdahiya@microsoft.com>