Documentation update for installation

[sarthakpati]

Fixes #N.A.

Proposed Changes

Checklist

• I have read the CONTRIBUTING guide
• My PR is based from the current GaNDLF master
• Non-breaking change (would not break existing functionality): please provide as many details as possible for any breaking change
• Function/class source code documentation added/updated
• Code has been blacked for style consistency
• If applicable, version information has been updated in GANDLF/version.py
• If adding a git submodule, add to list of exceptions for black styling in pyproject.toml file
• Usage documentation has been updated, if appropriate
• History has been updated, if appropriate
• Tests added or modified to cover the changes; if coverage is reduced, please give explanation
• If customized dependency installation is required (i.e., a separate pip install step is needed for PR to be functional), please ensure it is reflected in all the files that control the CI, namely: python-test.yml, and all docker files [1,2,3,4]

[codecov]

Codecov Report

Merging #403 (209fee8) into master (5094bf3) will increase coverage by 0.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #403      +/-   ##
==========================================
+ Coverage   92.25%   92.27%   +0.01%     
==========================================
  Files         101      101              
  Lines        6020     6020              
==========================================
+ Hits         5554     5555       +1     
+ Misses        466      465       -1     

Flag	Coverage Δ
unittests	92.27% <ø> (+0.01%)	⬆️

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

Impacted Files	Coverage Δ
...NDLF/data/preprocessing/template_matching/utils.py	97.67% <0.00%> (+2.32%)	⬆️

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