Add release notes for version 2.1.0#3773

Merged

Rishikesh1159 merged 9 commits intoopensearch-project:mainfrom

Rishikesh1159:2.1.0-release-notes

Jul 7, 2022

Commits on Jul 5, 2022

Commits on Jul 6, 2022

Removing unnecessary commits from release notes and add steps to generate release notes.
Rishikesh1159
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Merge branch '2.1.0-release-notes' of https://github.com/Rishikesh1159/OpenSearch into 2.1.0-release-notes
Rishikesh1159
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