Robust MIMO Example - Fix computation of Sigma

[rega0051]

python-control/examples/robust_mimo.py

Line 47 in 03183d1

sjw = (m*np.exp(1j*p*np.pi/180)).transpose(2, 0, 1)

freqresp returns the phase already returns the phase in units of radians.
Computation the complex response should be:
sjw = (m * np.exp(1j * p)).transpose(2, 0, 1)