[AUTO] Add release notes for 3.4.0 (#20181)

* Add release notes for 3.4.0

Signed-off-by: opensearch-ci <[email protected]>

* Cleanup commits related to Refactor stats classes to use Builder pattern

Using a single issue to replace multiple refactoring of similar classes

Signed-off-by: Sandesh Kumar <[email protected]>

* Add release notes for 3.4.0

Signed-off-by: opensearch-ci <[email protected]>

* Move CHANGELOG contents into release notes

Signed-off-by: Andrew Ross <[email protected]>

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Signed-off-by: opensearch-ci <[email protected]>
Signed-off-by: Sandesh Kumar <[email protected]>
Signed-off-by: Andrew Ross <[email protected]>
Co-authored-by: Sandesh Kumar <[email protected]>
Co-authored-by: Andrew Ross <[email protected]>

Author: 3 people