Plotting with units no longer labels axes

[SJaffa]

programming_with_python/_episodes/06-units_and_quantities.md

Line 315 in 19edfb7

plt.plot(angles, np.sin(angles))

The material shows automatic labels with degrees or radians but this doesn't work anymore

[lasse-cs]

This came up again in the running of the course on the 7th.

[martinherrerias]

I think this is a duplicate of #42, and now a triplicate with: #44