[jdk15u-dev] RFR: 8269356: Bump update version for OpenJDK: jdk-15.0.5

[Yuri Nesterenko]

a necessary update before starting a new release in this train. Note that we change the version in .jcheck/conf here in the same commit.

-------------

Commit messages:
 - 8269356: Bump update version for OpenJDK: jdk-15.0.5

Changes: https://git.openjdk.java.net/jdk15u-dev/pull/75/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk15u-dev&pr=75&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8269356
  Stats: 3 lines in 2 files changed: 0 ins; 0 del; 3 mod
  Patch: https://git.openjdk.java.net/jdk15u-dev/pull/75.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk15u-dev pull/75/head:pull/75

PR: https://git.openjdk.java.net/jdk15u-dev/pull/75