stem3() not working properly

[xarico10]

stem3() to plot a 3-D chart of discrete data points not working properly.

X = linspace(-pi/2,pi/2,40);
Z = cos(X);
stem3(Z)

fig2plotly(gcf, 'offline', false);

Expected and generated (https://chart-studio.plotly.com/~xarico10/635/#/) plots:

Examples on using stem3() can be found on:
https://www.mathworks.com/help/matlab/ref/stem3.html#btrijff-1

[gilbertogalvis]

PR #344 fix this issue