Clean up build dependencies

[tjni]

Describe what the PR does:

Cleans up the build dependencies in pyproject.toml.

Checklist:

• Confirm that one or more new tests are written for the new functionality.
• Run tests and ensure everything passes (with 100% test coverage).
• Update README.md with any new documentation.

[codeclimate]

Code Climate has analyzed commit 9eb12c4 and detected 0 issues on this pull request.

View more on Code Climate.

[bachya]

Thank you!

[codecov]

Codecov Report

Merging #207 (8c704c5) into dev (a2d63b6) will not change coverage.
The diff coverage is n/a.

❗ Current head 8c704c5 differs from pull request most recent head 9eb12c4. Consider uploading reports for the commit 9eb12c4 to get more accurate results

@@            Coverage Diff            @@
##               dev      #207   +/-   ##
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  Coverage   100.00%   100.00%           
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  Files           13        13           
  Lines          472       472           
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  Hits           472       472