[dev] restrict pylint to changed files

[cg505]

Use a similar approach to what we do with yapf to limit pylint to only files that have changed from master.

On my machine this shaves about a minute off pylint runtime, making pylint 7-8x faster and format.sh 3-4x faster.

Tested (run the relevant ones):

• [x] Code formatting: bash format.sh :)
• [ ] Any manual or new tests for this PR (please specify below)
• [ ] All smoke tests: pytest tests/test_smoke.py
• [ ] Relevant individual smoke tests: pytest tests/test_smoke.py::test_fill_in_the_name
• [ ] Backward compatibility tests: conda deactivate; bash -i tests/backward_compatibility_tests.sh