Merge branch 'rohlfing/update-matplotlib-dependencies' into 'master'

Matplotlib: removed use_line_collection since it is deprecated

See merge request !11

rwth_nb/plots/mpl_decorations.py

@@ -333,7 +333,7 @@ mcolors.get_named_colors_mapping().update(colors.rwth_colors)
 
 # Custom stem function
 def stem(ax, x, y, color='rwth:blue', **kwargs):
-    container = ax.stem(x, y, use_line_collection=True, basefmt=" ", **kwargs)
+    container = ax.stem(x, y, basefmt=" ", **kwargs)
     plt.setp(container, 'color', color)
     return container