Fix script to install ruby

[shinya7y]

echo 'source $HOME/.bash_profile' >> ~/.bashrc may cause an infinite loop.
Flowchart examples:
https://www.solipsys.co.uk/images/BashStartupFiles1.png
https://cdn-ak.f.st-hatena.com/images/fotolife/N/Naotsugu/20191110/20191110015450.png

[codecov]

Codecov Report

Merging #4360 (f41cc89) into master (482f60f) will increase coverage by 0.12%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #4360      +/-   ##
==========================================
+ Coverage   61.82%   61.94%   +0.12%     
==========================================
  Files         239      239              
  Lines       18265    18265              
  Branches     3058     3058              
==========================================
+ Hits        11292    11315      +23     
+ Misses       6425     6401      -24     
- Partials      548      549       +1     

Flag	Coverage Δ
unittests	61.91% <ø> (+0.12%)	⬆️

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Impacted Files	Coverage Δ
mmdet/models/roi_heads/mask_heads/maskiou_head.py	100.00% <0.00%> (+5.37%)	⬆️
mmdet/models/roi_heads/mask_scoring_roi_head.py	87.50% <0.00%> (+32.14%)	⬆️

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