Dataclasses removed from dependencies, bumped upload-artifact version to v3, and parallel unittests

[Raalsky]

Before submitting checklist

• Did you update the CHANGELOG? (not for test updates, internal changes/refactors or CI/CD setup)
• Did you asked the docs owner to review all the updated user-facing interfaces?

[codecov]

Codecov Report

Base: 79.43% // Head: 0.00% // Decreases project coverage by -79.44% ⚠️

Coverage data is based on head (03342a9) compared to base (1e8829f).
Patch has no changes to coverable lines.

Additional details and impacted files

@@            Coverage Diff             @@
##           master   #1267       +/-   ##
==========================================
- Coverage   79.43%   0.00%   -79.44%     
==========================================
  Files         281     281               
  Lines       13628   13628               
==========================================
- Hits        10825       0    -10825     
- Misses       2803   13628    +10825     

Flag	Coverage Δ
e2e	?
unit	?
unit-pull-request	0.00% <ø> (?)

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
src/neptune/envs.py	0.00% <0.00%> (-100.00%)	⬇️
src/neptune/utils.py	0.00% <0.00%> (-100.00%)	⬇️
src/neptune/new/run.py	0.00% <0.00%> (-100.00%)	⬇️
src/neptune/__init__.py	0.00% <0.00%> (-100.00%)	⬇️
src/neptune/new/envs.py	0.00% <0.00%> (-100.00%)	⬇️
src/neptune/constants.py	0.00% <0.00%> (-100.00%)	⬇️
src/neptune/new/utils.py	0.00% <0.00%> (-100.00%)	⬇️
src/neptune/common/envs.py	0.00% <0.00%> (-100.00%)	⬇️
src/neptune/legacy/envs.py	0.00% <0.00%> (-100.00%)	⬇️
src/neptune/new/handler.py	0.00% <0.00%> (-100.00%)	⬇️
... and 248 more

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