Update README to describe max_dim argument

[kevinsung]

The section

The subspace dimension is set indirectly

should be updated now that the max_dim argument allows setting a direct limit on the subspace dimension

[Alistarco]

Hi, I'd like to work on this issue if it's still available. Could you assign it to me?

[caleb-johnson]

Hi, I'd like to work on this issue if it's still available. Could you assign it to me?

Hey thanks for the interest in helping out. We're in the process of migrating our docs to the IBM Quantum Platform right now, so I will probably handle this particular change.

[Alistarco]

I understand, no problem.