git: openjdk/jdk: 8296153: Bump minimum boot jdk to JDK 20

[Mikael Vidstedt]

Changeset: cb158ffb
Author:    Mikael Vidstedt <mikael at openjdk.org>
Date:      2023-04-21 20:51:50 +0000
URL:       https://git.openjdk.org/jdk/commit/cb158ffb8a5be3322c914d93752d12327bc6f352

8296153: Bump minimum boot jdk to JDK 20

Reviewed-by: erikj, darcy, iris

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