[jdk21u] RFR: JDK-8315688: Update jdk21u fix version to 21.0.2

[Rob McKenna]

Update fix version

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Commit messages:
 - JDK-8315688: Update jdk21u fix version to 21.0.2

Changes: https://git.openjdk.org/jdk21u/pull/137/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk21u&pr=137&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8315688
  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk21u/pull/137.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u.git pull/137/head:pull/137

PR: https://git.openjdk.org/jdk21u/pull/137