Bump golang to version 1.21 on release branch

[rahulbabu95]

Issue #, if available: The Govulncheck has been failing on release branch 19 for quite sometime now. We need to bump multiple items on release branch to fix the govulncheck. While the check would still fail until we bump the helm to version 3.14.x, this change should at least mitigate the CVEs associated with go 1.20.x.

Description of changes:

Testing (if applicable):

Documentation added/planned (if applicable):

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Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

:exclamation: No coverage uploaded for pull request base (release-0.19@589fa65). Click here to learn what that means.

Additional details and impacted files

@@               Coverage Diff               @@
##             release-0.19    #8103   +/-   ##
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  Coverage                ?   73.53%           
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  Files                   ?      588           
  Lines                   ?    37186           
  Branches                ?        0           
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  Hits                    ?    27344           
  Misses                  ?     8049           
  Partials                ?     1793           

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[rahulbabu95]

Closing as release branch golang version has been bumped to 1.21.