[MAINT] pin dependencies for docker build

[Remi-Gau]

closes #51

• add a requirements.txt generated from a pip freeze to be used during the docker build
• freeze non python dependencies used during docker build
• pin docker base image with sha256

[codecov-commenter]

Codecov Report

Merging #59 (8871f33) into main (916e155) will not change coverage.
The diff coverage is n/a.

Additional details and impacted files

@@           Coverage Diff           @@
##             main      #59   +/-   ##
=======================================
  Coverage   91.31%   91.31%           
=======================================
  Files           9        9           
  Lines         449      449           
=======================================
  Hits          410      410           
  Misses         39       39           

[htwangtw]

Thanks for getting this one in...