[sonic-linkmgrd][master] submodule updates (sonic-net#10925)

[sonic-linkmgrd][master] submodule updates

d744bfb Longxiang Lyu Wed May 25 08:40:42 2022 +0800 Support switch between using wellknown mac or server mac addr (#73)
684e989 Jing Zhang Wed May 18 09:59:02 2022 -0700 Avoid switching active when LinkState == Down (#77)
e4aa4fd Longxiang Lyu Tue May 17 09:13:23 2022 +0800 [Makefile] Remove redundant optimization options (#75)
4ec7505 Jing Zhang Thu May 12 08:19:20 2022 -0700 [ci]: uplift diff coverage threshold to 80% (#71)

sign-off: Jing Zhang zhangjing@microsoft.com