[jfx15] RFR: 8255272: Create release notes for JavaFX 15.0.1

[Johan Vos]

releasenotes for JavaFX 15.0.1

-------------

Commit messages:
 - Add security fixes
 - Create release notes for JavaFX 15.0.1

Changes: https://git.openjdk.java.net/jfx/pull/335/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jfx&pr=335&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8255272
  Stats: 21 lines in 1 file changed: 21 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/jfx/pull/335.diff
  Fetch: git fetch https://git.openjdk.java.net/jfx pull/335/head:pull/335

PR: https://git.openjdk.java.net/jfx/pull/335