BUG: PeriodIndex.unique results in Int64Index
Merge pull request #7843 from sinhrks/punique

BUG: PeriodIndex.unique results in Int64Index
BUG/VIS: rot and fontsize are not applied to minor ticks
CLN: cln tslib, frequencies
BUG: don't force date parsing in read_html

Necessitates the deprecation of the ``infer_types`` argument.
Merge pull request #7851 from cpcloud/read-html-date-parsing

BUG: fix greedy date parsing in read_html
Merge pull request #7854 from sinhrks/tslib_cln

CLN: Clean tslib, frequencies import
Merge pull request #7844 from sinhrks/minor_rot

BUG/VIS: rot and fontsize are not applied to timeseries plots
BUG: fix multi-column sort that includes Categoricals (GH7848)
CLN: refactor _lexsort_indexer to use Categoricals