Fix documentation links

[JihwanEom]

Summary

• Fix broken documentation links

How to test

Checklist

• I have added unit tests to cover my changes.​
• I have added integration tests to cover my changes.​
• I have added the description of my changes into CHANGELOG.​
• I have updated the documentation accordingly

License

• I submit my code changes under the same MIT License that covers the project.
  Feel free to contact the maintainers if that's a concern.
• I have updated the license header for each file (see an example below).

# Copyright (C) 2023 Intel Corporation
#
# SPDX-License-Identifier: MIT

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[codecov-commenter]

Codecov Report

Patch and project coverage have no change.

Comparison is base (769c620) 78.70% compared to head (bc15acb) 78.70%.

Additional details and impacted files

@@           Coverage Diff            @@
##           develop     #972   +/-   ##
========================================
  Coverage    78.70%   78.70%           
========================================
  Files          231      231           
  Lines        26420    26420           
  Branches      5258     5258           
========================================
  Hits         20795    20795           
  Misses        4400     4400           
  Partials      1225     1225           

Flag	Coverage Δ
macos-11_Python-3.8	77.73% <ø> (+<0.01%)	⬆️
ubuntu-20.04_Python-3.8	78.69% <ø> (ø)
windows-2019_Python-3.8	78.59% <ø> (ø)

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

Impacted Files	Coverage Δ
datumaro/cli/util/__init__.py	26.22% <ø> (ø)

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[vinnamkim]

• Fix for Broken links in README.md and contributing.md #971

[vinnamkim]

LGTM.