update CHANGES.md release notes to reflect delay in package release

[imatiach-msft]

Description

Due to release delay, a few more PRs were merged before the pypi release was completed.
Hence, this PR updates the CHANGES.md release notes to reflect delay in 0.20.0 package release.

Checklist

• I have added screenshots above for all UI changes.
• I have added e2e tests for all UI changes.
• Documentation was updated if it was needed.

[codecov-commenter]

Codecov Report

Merging #1581 (d3ac128) into main (e3d0f24) will increase coverage by 1.70%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             main    #1581      +/-   ##
==========================================
+ Coverage   88.04%   89.75%   +1.70%     
==========================================
  Files         109       38      -71     
  Lines        5295     1610    -3685     
==========================================
- Hits         4662     1445    -3217     
+ Misses        633      165     -468     

Flag	Coverage Δ
unittests	89.75% <ø> (+1.70%)	⬆️

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Impacted Files	Coverage Δ
raiwidgets/raiwidgets/explanation_constants.py
raiwidgets/raiwidgets/dashboard.py
...tabalanceanalysis/distribution_balance_measures.py
raiwidgets/raiwidgets/__init__.py
raiwidgets/raiwidgets/__version__.py
.../responsibleai/modelanalysis/constants/__init__.py
...ibleai/_tools/causal/dashboard_schemas/__init__.py
...ponsibleai/responsibleai/_tools/causal/__init__.py
...ponsibleai/responsibleai/rai_insights/constants.py
...i/responsibleai/managers/counterfactual_manager.py
... and 61 more

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[github-actions]

https://responsibleai.blob.core.windows.net/pullrequest/microsoft/responsible-ai-toolbox/ilmat/update-release-notes/dashboard/index.html