Tagging release 6.4.0 on branch main.

about: bump version to next v6.4.0-(rc)

Signed-off-by: Rohit Yadav <[email protected]>

update changes.md file (apache#134)

* Update CHANGES.md

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Co-authored-by: Boris Stoyanov <[email protected]>
Co-authored-by: Rohit Yadav <[email protected]>

cmk: fix formating using gofmt

Signed-off-by: Rohit Yadav <[email protected]>

Tagging release 6.1.0 on branch master.

Tagging release 6.0.0 on branch master.

Tagging release 5.3.3 on branch master.

Tagging release 5.3.2 on branch master.

Tagging release 5.3.1 on branch master.

Tagging release 5.3.0 on branch 5.3.