The github action hooks didn't run the unit tests on the expanders
update in #4233 (likely the known "tests don't run automatically for
new contributor" limitation).
NewStrategy became NewFilter, with a BestOptions (plural) method,
and returns a Options slice instead of a single Option.
Multiple expanders can now be specified, expanders now "filter to the
tied for best" instead of "selecting the best" so the output of one
expander is now fed to the input of the next. Each expander may only
be used once to disallow bad configuration. This should not be a change
in functionality as in the event of a tie the random expander is still
used.
The following things changed in scheduler and needed to be fixed:
* NodeInfo was moved to schedulerframework
* Some fields on NodeInfo are now exposed directly instead of via getters
* NodeInfo.Pods is now a list of *schedulerframework.PodInfo, not *apiv1.Pod
* SharedLister and NodeInfoLister were moved to schedulerframework
* PodLister was removed
If a group doesn't match any of the regexes in the priorities list it won't
be considered for expansion, which could catch some users off-guard.
Document this behavior.