Include explicit package data

[blink1073]

Workaround for pypa/setuptools#3200

[codecov-commenter]

Codecov Report

Merging #757 (c211dbb) into main (cd1b1b8) will decrease coverage by 0.11%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             main     #757      +/-   ##
==========================================
- Coverage   70.68%   70.56%   -0.12%     
==========================================
  Files          62       62              
  Lines        7620     7620              
  Branches     1218     1218              
==========================================
- Hits         5386     5377       -9     
- Misses       1860     1872      +12     
+ Partials      374      371       -3     

Impacted Files	Coverage Δ
jupyter_server/base/zmqhandlers.py	52.91% <0.00%> (-4.24%)	⬇️
jupyter_server/services/kernels/handlers.py	58.86% <0.00%> (-0.22%)	⬇️

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[blink1073]

I'm not going to release this until Monday, regardless of the whether setuptools gets a release, because it only affects new wheels built from our sdist. I don't want to risk making a release on Friday.