git: openjdk/jdk15u-dev: 8278997: Bump update version for OpenJDK: jdk-15.0.7

[Yuri Nesterenko]

Changeset: 9beff4a0
Author:    Yuri Nesterenko <yan at openjdk.org>
Date:      2021-12-20 12:01:35 +0000
URL:       https://git.openjdk.java.net/jdk15u-dev/commit/9beff4a0af57a10befc9d9a787a2fb46e29c0dec

8278997: Bump update version for OpenJDK: jdk-15.0.7

Reviewed-by: bae

! .jcheck/conf
! make/autoconf/version-numbers