[jdk11u-dev] RFR: 8373254: Bump update version of OpenJDK: 11.0.31

[Andrew John Hughes]

Rampdown for 11.0.30 [has begun](https://mail.openjdk.org/pipermail/jdk-updates-dev/2025-December/050769.html). 11u-dev needs to transition to 11.0.31.

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Commit messages:
 - 8373254: Bump update version of OpenJDK: 11.0.31

Changes: https://git.openjdk.org/jdk11u-dev/pull/3132/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk11u-dev&pr=3132&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8373254
  Stats: 4 lines in 2 files changed: 0 ins; 0 del; 4 mod
  Patch: https://git.openjdk.org/jdk11u-dev/pull/3132.diff
  Fetch: git fetch https://git.openjdk.org/jdk11u-dev.git pull/3132/head:pull/3132

PR: https://git.openjdk.org/jdk11u-dev/pull/3132