Fix add_vline and add_hline with datetime axes - #5508

Fix add_vline and add_hline with datetime axes#5508

emilykl merged 6 commits into

plotly:mainplotly/plotly.py:mainfrom

mosh3eb:fix/add-vline-datetime-annotationmosh3eb/plotly.py:fix/add-vline-datetime-annotationCopy head branch name to clipboard