Update setup.py

[bjtho08]

Changed dependencies to require matplotlib>=2.2.3 rather than ==2.2.3. This should avoid unintended downgrading of matplotlib for end users.

Sanity

• [x] I'm aware of the implications of the proposed changes
• [x] Code is PEP8
• [x] I'm making the PR to master

Tests

• [ ] Changes have gone through actual use testing
• [ ] All local tests have passed (run python test_script.py)
• [ ] Tests have been updated to reflect the changes

I have intentionally not performed these tests due to the insignificance of the change.

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[pep8speaks]

Hello @bjtho08! Thanks for updating this PR. We checked the lines you've touched for PEP 8 issues, and found:

• In the file setup.py:

Line 8:80: E501 line too long (80 > 79 characters)

[mikkokotila]

Thanks. Graphs are now entirely out of the package, so removed matplotlib from deps.

[bjtho08]

I'm happy to help whenever I can :)