[sonic-swss-common] Update submodule (#6317)

Including commits in sonic-swss-common repo:

b423b9c Add support for hexists call (#432) [Tony Titus]
0982996 Remove extension of tableNameSeparatorMap (#430) [Qi Luo]
d16cc76 [build]: add azure pipeline build badge (#429) [lguohan]
f2aaf55 Set up CI with Azure Pipelines (#428) [lguohan]