chore(deps): update go to v1.21.4 (patch)

[cilium-renovate]

This PR contains the following updates:

Package	Type	Update	Change
docker.io/library/golang		patch	1.21.3-alpine -> 1.21.4-alpine
docker.io/library/golang	final	patch	1.21.3 -> 1.21.4
docker.io/library/golang	stage	patch	1.21.3 -> 1.21.4
go (source)		patch	1.21.3 -> 1.21.4
go (source)	golang	patch	1.21.3 -> 1.21.4

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