Clean backport of new `SECURITY.md` file to the `jfx23u` repo. -------------
Commit messages: - Backport 0dd0c794c3b08f816e7618026d5c90deaf952046 Changes: https://git.openjdk.org/jfx23u/pull/23/files Webrev: https://webrevs.openjdk.org/?repo=jfx23u&pr=23&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8340954 Stats: 3 lines in 1 file changed: 3 ins; 0 del; 0 mod Patch: https://git.openjdk.org/jfx23u/pull/23.diff Fetch: git fetch https://git.openjdk.org/jfx23u.git pull/23/head:pull/23 PR: https://git.openjdk.org/jfx23u/pull/23
