Bump Numpy version and fix complex type

[WolfByttner]

No description provided.

[codecov]

Codecov Report

Attention: Patch coverage is 77.19298% with 13 lines in your changes are missing coverage. Please review.

Project coverage is 76.51%. Comparing base (d4c5ff3) to head (0571684).

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #102      +/-   ##
==========================================
+ Coverage   76.14%   76.51%   +0.37%     
==========================================
  Files          25       26       +1     
  Lines        2691     2670      -21     
==========================================
- Hits         2049     2043       -6     
+ Misses        642      627      -15     

Flag	Coverage Δ
unittests	76.51% <77.19%> (+0.37%)	⬆️

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Files	Coverage Δ
traja/__init__.py	91.66% <100.00%> (ø)
traja/core.py	100.00% <100.00%> (ø)
traja/dataset/__init__.py	100.00% <100.00%> (ø)
traja/dataset/dataset.py	100.00% <ø> (+1.57%)	⬆️
traja/dataset/example.py	100.00% <100.00%> (ø)
traja/dataset/pedestrian.py	90.32% <100.00%> (+60.32%)	⬆️
traja/frame.py	83.82% <100.00%> (-0.63%)	⬇️
traja/models/__init__.py	100.00% <100.00%> (ø)
traja/models/inference.py	31.42% <ø> (ø)
traja/models/losses.py	96.42% <100.00%> (ø)
... and 8 more

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[JustinShenk]

Good work!