Remove use of matplotlib Axes.set_ylim keyword ymin (#3279) (#3280)

* Remove use of ymin matplotlib keyword

* Documented fix of #3279 in release notes

Author: JohnPaton

RELEASE-NOTES.md

@@ -16,6 +16,7 @@
 - Big rewrite of documentation (#3275)
 - Fixed Triangular distribution `c` attribute handling in `random` and updated sample codes for consistency (#3225)
 - Refactor SMC and properly compute marginal likelihood (#3124)
+- Removed use of deprecated `ymin` keyword in matplotlib's `Axes.set_ylim` (#3279)
 
 ### Deprecations
 

pymc3/plots/traceplot.py

@@ -142,7 +142,7 @@ def traceplot(trace, varnames=None, transform=identity_transform, figsize=None,
                 ax[i, j].relim()
                 ax[i, j].autoscale_view(True, True, True)
             ax[i, 1].set_xlim(x0, x0 + width)
-        ax[i, 0].set_ylim(ymin=0)
+        ax[i, 0].set_ylim(bottom=0)
     if live_plot:
         ax[0, 0].figure.canvas.draw()
     plt.tight_layout()