[JDK-8297068](https://bugs.openjdk.org/browse/JDK-8297068) updated boot JDK to 19.0.1 from 18.0.2, and [JDK-8321434](https://bugs.openjdk.org/browse/JDK-8321434) updated boot JDK to 21.0.1. `CONTRIBUTING.md` should be updated correspondingly.
------------- Commit messages: - 8325093: Update CONTRIBUTING.md for build jdk version Changes: https://git.openjdk.org/jfx/pull/1357/files Webrev: https://webrevs.openjdk.org/?repo=jfx&pr=1357&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8325093 Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod Patch: https://git.openjdk.org/jfx/pull/1357.diff Fetch: git fetch https://git.openjdk.org/jfx.git pull/1357/head:pull/1357 PR: https://git.openjdk.org/jfx/pull/1357
