API: change default behaviour of str.match from deprecated extract to match (GH5224)
I just stumbled on this, and seems we didn't have this in our deprecations to do list (https://github.com/pandas-dev/pandas/issues/6581).

This PR changes the default behaviour of `str.match` from extracting groups to just a match (True/False). The previous default behaviour was deprecated since 0.13.0 (https://github.com/pandas-dev/pandas/pull/5224)