Log Message:
py-matplotlib: updated to 3.4.1

What's new in Matplotlib 3.4.0

* Figure and Axes creation / management
 - New subfigure functionality
 - Single-line string notation for subplot_mosaic
 - Changes to behavior of Axes creation methods (gca, add_axes, add_subplot)
 - add_subplot/add_axes gained an axes_class parameter
 - Subplot and subplot2grid can now work with constrained layout
* Plotting methods
 - axline supports transform parameter
 - New automatic labeling for bar charts
 - A list of hatches can be specified to bar and barh
 - Setting BarContainer orientation
 - Contour plots now default to using ScalarFormatter
 - Axes.errorbar cycles non-color properties correctly
 - errorbar errorevery parameter matches markevery
 - hexbin supports data reference for C parameter
 - Support callable for formatting of Sankey labels
 - Axes.spines access shortcuts
 - New stairs method and StepPatch artist
 - Added orientation parameter for stem plots
 - Angles on Bracket arrow styles
 - TickedStroke patheffect
* Colors and colormaps
 - Collection color specification and mapping
 - Transparency (alpha) can be set as an array in collections
 - pcolormesh has improved transparency handling by enabling snapping
 - IPython representations for Colormap objects
 - Colormap.set_extremes and Colormap.with_extremes
 - Get under/over/bad colors of Colormap objects
 - New cm.unregister_cmap function
 - New CenteredNorm for symmetrical data around a center
 - New FuncNorm for arbitrary normalizations
 - GridSpec-based colorbars can now be positioned above or to the left of the \ 
main axes
* Titles, ticks, and labels
 - supxlabel and supylabel
 - Shared-axes subplots tick label visibility is now correct for top or left labels
 - An iterable object with labels can be passed to Axes.plot
* Fonts and Text
 - Text transform can rotate text direction
 - matplotlib.mathtext now supports overset and underset LaTeX symbols
 - math_fontfamily parameter to change Text font family
 - TextArea/AnchoredText support horizontalalignment
 - PDF supports URLs on Text artists
* rcParams improvements
 - New rcParams for dates: set converter and whether to use interval_multiples
 - Date formatters now respect usetex rcParam
 - Setting image.cmap to a Colormap
 - Tick and tick label colors can be set independently using rcParams
* 3D Axes improvements
 - Errorbar method in 3D Axes
 - Stem plots in 3D Axes
 - 3D Collection properties are now modifiable
 - Panning in 3D Axes
* Interactive tool improvements
 - New RangeSlider widget
 - Sliders can now snap to arbitrary values
 - Pausing and Resuming Animations
* Sphinx extensions
 - plot_directive caption option
* Backend-specific improvements
 - Consecutive rasterized draws now merged
 - Support raw/rgba frame format in FFMpegFileWriter
 - nbAgg/WebAgg support middle-click and double-click
 - nbAgg support binary communication
 - Indexed color for PNG images in PDF files when possible
 - Improved font subsettings in PDF/PS
 - Kerning added to strings in PDFs
 - Fully-fractional HiDPI in QtAgg
 - wxAgg supports fullscreen toggle