Merge branch '404-nightly-c-i-breaking' into 'master'

Resolve "Nightly C.I. breaking"

Closes #404

See merge request lscsoft/bilby!578

bilby/gw/prior_files/GW150914.prior

+mass_ratio = Uniform(name='mass_ratio', minimum=0.125, maximum=1, boundary='reflective')
+chirp_mass = Uniform(name='chirp_mass', minimum=25, maximum=31, unit='$M_{\odot}$', boundary='reflective')
+mass_1 = Constraint(name='mass_1', minimum=10, maximum=80)
+mass_2 = Constraint(name='mass_2', minimum=10, maximum=80)
+a_1 = Uniform(name='a_1', minimum=0, maximum=0.99, boundary='reflective')
+a_2 = Uniform(name='a_2', minimum=0, maximum=0.99, boundary='reflective')
+tilt_1 = Sine(name='tilt_1', boundary='reflective')
+tilt_2 = Sine(name='tilt_2', boundary='reflective')
+phi_12 = Uniform(name='phi_12', minimum=0, maximum=2 * np.pi, boundary='periodic')
+phi_jl = Uniform(name='phi_jl', minimum=0, maximum=2 * np.pi, boundary='periodic')
+luminosity_distance = PowerLaw(alpha=2, name='luminosity_distance', minimum=50, maximum=2000, unit='Mpc', latex_label='$d_L$')
+dec =  Cosine(name='dec', boundary='reflective')
+ra =  Uniform(name='ra', minimum=0, maximum=2 * np.pi, boundary='periodic')
+theta_jn =  Sine(name='theta_jn', boundary='reflective')
+psi =  Uniform(name='psi', minimum=0, maximum=np.pi, boundary='periodic')
+phase =  Uniform(name='phase', minimum=0, maximum=2 * np.pi, boundary='periodic')