PKG, TESTS: msgpack-python package was renamed on PyPI, add entry point test

[hoechenberger]

No description provided.

[codecov-io]

Codecov Report

Merging #2502 into master will decrease coverage by 0.13%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #2502      +/-   ##
==========================================
- Coverage   44.65%   44.52%   -0.14%     
==========================================
  Files         232      232              
  Lines       40257    40257              
  Branches     6915     6915              
==========================================
- Hits        17978    17925      -53     
- Misses      20413    20439      +26     
- Partials     1866     1893      +27

Impacted Files	Coverage Δ
psychopy/app/pavlovia_ui/toolbar.py	70.58% <0%> (-3.93%)	⬇️
psychopy/app/icons.py	77.41% <0%> (-3.23%)	⬇️
psychopy/app/pavlovia_ui/functions.py	17.72% <0%> (-2.54%)	⬇️
psychopy/app/builder/builder.py	50.76% <0%> (-1.67%)	⬇️
psychopy/app/builder/validators.py	63.76% <0%> (-1.45%)	⬇️
psychopy/app/coder/coder.py	28.26% <0%> (-1.2%)	⬇️
psychopy/app/builder/flow.py	35.88% <0%> (-0.69%)	⬇️
psychopy/app/_psychopyApp.py	37.31% <0%> (-0.62%)	⬇️
psychopy/tools/wizard.py	73.3% <0%> (-0.44%)	⬇️
psychopy/app/dialogs.py	27.68% <0%> (ø)	⬆️
... and 2 more

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[coveralls]

Coverage decreased (-0.06%) to 49.238% when pulling da7b84d on hoechenberger:msgpack into fb86167 on psychopy:master.