How to disable auto-indent for a specific mode?

[Pankaj Jangid]

I am using plantuml-mode for some UML diagrams. But I discovered that
the auto-indent is broken. And the project doesn’t seem to be
active. But to be honest, I haven’t yet contacted the maintainer of the
package. I’ll definitely do.

For the time being, I want to disable auto-indent for this particular
mode? Is there a way to suppress that? Or is this something that is
controlled by a mode specific variable?

-- 
Regards ~Pankaj