Update registry.access.redhat.com/ubi9/go-toolset Docker tag to v1.21

[red-hat-konflux[bot]]

This PR contains the following updates:

Package	Type	Update	Change
registry.access.redhat.com/ubi9/go-toolset	stage	minor	1.20 -> 1.21

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This PR has been generated by Renovate Bot.

[app-sre-bot]

Can one of the admins verify this patch?