update to holiday to help with GH#7070
BUG: Timestamp cannot parse nanosecond from string
Merge pull request #7907 from sinhrks/parse_ns2

BUG: Timestamp cannot parse nanosecond from string
Merge pull request #7913 from MichaelWS/master

update to holiday to help with GH#7070
ENH/CLN: add HistPlot class inheriting MPLPlot