fix linting in bpz_lite, try bumping codecov workflow version

[sschmidt23]

Problem & Solution Description (including issue #)

a few minor linting changes in bpz_lite to get rid of some whitespace, test whether v4 of codecov action works where v3 is failing.

Code Quality

• My code follows the code style of this project
• I have written unit tests or justified all instances of #pragma: no cover; in the case of a bugfix, a new test that breaks as a result of the bug has been added
• My code contains relevant comments and necessary documentation for future maintainers; the change is reflected in applicable demos/tutorials (with output cleared!) and added/updated docstrings use the NumPy docstring format
• Any breaking changes, described above, are accompanied by backwards compatibility and deprecation warnings

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 100.00%. Comparing base (2dadd3f) to head (50717ff).

Additional details and impacted files

@@            Coverage Diff            @@
##              main       #48   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files            3         3           
  Lines          242       242           
=========================================
  Hits           242       242           

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