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.
Daniel Kłobuszewski
Benjamin Pineau
Ryan McNamara
Johannes Brück
Lukasz Piatkowski
Łukasz Osipiuk