Add back missing import.

QuLogic · QuLogic · commit b483497b1695 · 2020-03-24T16:42:54.000-04:00
Some crossed PRs removed this import when it was needed by a different
PR.
diff --git a/lib/matplotlib/backends/backend_agg.py b/lib/matplotlib/backends/backend_agg.py
@@ -37,6 +37,7 @@
 
 import matplotlib as mpl
 from matplotlib import cbook
+from matplotlib import colors as mcolors
 from matplotlib.backend_bases import (
     _Backend, FigureCanvasBase, FigureManagerBase, RendererBase)
 from matplotlib.font_manager import findfont, get_font
