[Fix] fix visualization in sot demo

[ToumaKazusa3]

This PR fixs the visualization in sot demo. In function cv2.rectangle, the coordinate points of the bbox need to be np.int instead of np.float. For more details, please refer to here.

[codecov]

Codecov Report

Merging #213 (6a99fd2) into master (11d2a1c) will increase coverage by 0.02%.
The diff coverage is 42.85%.

@@            Coverage Diff             @@
##           master     #213      +/-   ##
==========================================
+ Coverage   69.64%   69.67%   +0.02%     
==========================================
  Files          87       87              
  Lines        4395     4402       +7     
  Branches      863      863              
==========================================
+ Hits         3061     3067       +6     
- Misses       1047     1048       +1     
  Partials      287      287              

Flag	Coverage Δ
unittests	69.60% <42.85%> (-0.02%)	⬇️

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

Impacted Files	Coverage Δ
mmtrack/models/sot/base.py	49.51% <42.85%> (-0.49%)	⬇️
mmtrack/datasets/pipelines/transforms.py	85.31% <0.00%> (-2.82%)	⬇️
mmtrack/datasets/sot_train_dataset.py	81.81% <0.00%> (-1.02%)	⬇️
mmtrack/models/mot/trackers/tracktor_tracker.py	78.57% <0.00%> (+15.47%)	⬆️

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[GT9505]

(4, )

[GT9505]

(4, ).