[jfx11u] RFR: 8294722: FX: Update copyright year in docs, readme files to 2023

[Ambarish Rapte]

Clean backport.

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Commit messages:
 - 8294722: FX: Update copyright year in docs, readme files to 2023

Changes: https://git.openjdk.org/jfx11u/pull/123/files
 Webrev: https://webrevs.openjdk.org/?repo=jfx11u&pr=123&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8294722
  Stats: 3 lines in 3 files changed: 0 ins; 0 del; 3 mod
  Patch: https://git.openjdk.org/jfx11u/pull/123.diff
  Fetch: git fetch https://git.openjdk.org/jfx11u pull/123/head:pull/123

PR: https://git.openjdk.org/jfx11u/pull/123