Update guide from v0.8 to v0.9

[stephane-caron]

As some of you have noticed, the API for creating and integrating configurations has been updated from v0.8 to v0.9 of the library. Here is a quick guide to update your existing code:

Creating a configuration

Before:

configuration = pink.apply_configuration(robot, q)

After:

configuration = pink.Configuration(robot.model, robot.data, q)

Integrating a velocity

Before:

q = self.configuration.integrate(velocity, dt)
configuration = pink.apply_configuration(robot, q)

After:

configuration.integrate_inplace(velocity, dt)