[jfx21u] RFR: 8315864: Change JavaFX release version to 21.0.2 in jfx21u

[Kevin Rushforth]

Updates for the beginning of the 21.0.2 release.

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Commit messages:
 - 8315864: Change JavaFX release version to 21.0.2 in jfx21u

Changes: https://git.openjdk.org/jfx21u/pull/13/files
 Webrev: https://webrevs.openjdk.org/?repo=jfx21u&pr=13&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8315864
  Stats: 2 lines in 2 files changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jfx21u/pull/13.diff
  Fetch: git fetch https://git.openjdk.org/jfx21u.git pull/13/head:pull/13

PR: https://git.openjdk.org/jfx21u/pull/13