[Docker] fix cv2 import error of ligGL.so.1

[aboettcher]

When I train a faster_rcnn network with the current docker script I get the following error:

Traceback (most recent call last):
  File "tools/train.py", line 8, in <module>
    import mmcv
  File "/opt/conda/lib/python3.7/site-packages/mmcv/__init__.py", line 4, in <module>
    from .fileio import *
  File "/opt/conda/lib/python3.7/site-packages/mmcv/fileio/__init__.py", line 4, in <module>
    from .io import dump, load, register_handler
  File "/opt/conda/lib/python3.7/site-packages/mmcv/fileio/io.py", line 4, in <module>
    from ..utils import is_list_of, is_str
  File "/opt/conda/lib/python3.7/site-packages/mmcv/utils/__init__.py", line 29, in <module>
    from .env import collect_env
  File "/opt/conda/lib/python3.7/site-packages/mmcv/utils/env.py", line 8, in <module>
    import cv2
  File "/opt/conda/lib/python3.7/site-packages/cv2/__init__.py", line 5, in <module>
    from .cv2 import *
ImportError: libGL.so.1: cannot open shared object file: No such file or directory

If found a solution to this problem at stackoverflow

In the pull request I added the listed packages in the stackoverflow thread linked above into the existing list of packages.

With the fix I can train models as expected.

[CLAassistant]

All committers have signed the CLA.

[codecov]

Codecov Report

Merging #3891 into master will decrease coverage by 0.32%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #3891      +/-   ##
==========================================
- Coverage   62.34%   62.01%   -0.33%     
==========================================
  Files         219      219              
  Lines       16273    16193      -80     
  Branches     2760     2760              
==========================================
- Hits        10145    10042     -103     
- Misses       5632     5657      +25     
+ Partials      496      494       -2     

Flag	Coverage Δ
#unittests	62.01% <ø> (-0.33%)	⬇️

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

Impacted Files	Coverage Δ
mmdet/models/roi_heads/mask_scoring_roi_head.py	58.92% <0.00%> (-32.15%)	⬇️
mmdet/models/roi_heads/mask_heads/maskiou_head.py	92.22% <0.00%> (-5.63%)	⬇️
mmdet/core/bbox/coder/base_bbox_coder.py	75.00% <0.00%> (-5.00%)	⬇️
mmdet/models/roi_heads/base_roi_head.py	76.31% <0.00%> (-3.69%)	⬇️
mmdet/models/detectors/base.py	47.54% <0.00%> (-3.23%)	⬇️
mmdet/models/detectors/htc.py	87.50% <0.00%> (-1.39%)	⬇️
mmdet/models/necks/pafpn.py	41.86% <0.00%> (-1.33%)	⬇️
mmdet/core/bbox/samplers/base_sampler.py	73.17% <0.00%> (-1.25%)	⬇️
mmdet/models/losses/gfocal_loss.py	45.28% <0.00%> (-1.02%)	⬇️
mmdet/models/dense_heads/base_dense_head.py	89.47% <0.00%> (-1.01%)	⬇️
... and 25 more

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