Backport PR #15168 on branch v3.1.x (MNT: explicitly cast np.bool_ -> bool to prevent deprecation warning)#15185

tacaswell merged 1 commit intomatplotlib:v3.1.xmatplotlib/matplotlib:v3.1.xfrom

meeseeksmachine:auto-backport-of-pr-15168-on-v3.1.xmeeseeksmachine/matplotlib:auto-backport-of-pr-15168-on-v3.1.xCopy head branch name to clipboard