Add what's new file for new color cycle

Perseudonymous · dstansby · commit 34114de96194 · 2017-11-11T09:58:56.000Z
diff --git a/doc/users/next_whats_new/new_color_cycle.rst b/doc/users/next_whats_new/new_color_cycle.rst
@@ -0,0 +1,4 @@
+New colorblind-friendly color cycle
+===================================
+
+A new color cycle has been added, tableau-colorblind10, to provide another option for colorblind-friendly plots.
