[jfx21u] RFR: 8366877: Change JavaFX release version to 21.0.9 in jfx21u

[Johan Vos]

Increase the version to 21.0.9

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Commit messages:
 - Change version to 21.0.9

Changes: https://git.openjdk.org/jfx21u/pull/101/files
  Webrev: https://webrevs.openjdk.org/?repo=jfx21u&pr=101&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8366877
  Stats: 2 lines in 2 files changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jfx21u/pull/101.diff
  Fetch: git fetch https://git.openjdk.org/jfx21u.git pull/101/head:pull/101

PR: https://git.openjdk.org/jfx21u/pull/101