Bump JDK21 version to 21.0.6+7

[github-actions]

Bump JDK21 version for all Linux images

Bump JDK21 version for Linux images in the docker-bake.hcl file

changes detected: path "variable.JAVA21_VERSION.default" updated from "21.0.5_11" to "21.0.6_7" in file "docker-bake.hcl"

21.0.6+7

https://adoptium.net/temurin/release-notes/?version=jdk-21.0.6+7

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