Fix CI failures

.gitlab-ci.yml

.pre-commit-config.yaml

bilby/bilby_mcmc/sampler.py

examples/core_examples/conditional_prior.py

examples/core_examples/gaussian_example.py

examples/core_examples/hyper_parameter_example.py

examples/core_examples/occam_factor_example.py

examples/core_examples/slabspike_example.py

test/integration/example_test.py