CHANGES.md, NEWS.md: update for 3.6.2

CHANGES.md, NEWS.md: update for 3.6.2

3.6.2 CHANGES.md includes the following:
 * CVE-2026-2673, CVE-2026-28386, CVE-2026-28387, CVE-2026-28388,
   CVE-2026-28389, CVE-2026-28390, CVE-2026-31789, CVE-2026-31790
 * https://github.com/openssl/openssl/pull/30384
   "Fix #19891 CONNECT request for IPv6 targets in OSSL_HTTP_proxy_connect"
 * https://github.com/openssl/openssl/pull/30411
   "Fix detection of plaintext HTTP over TLS (3.6/3.5 backport)"
 * https://github.com/openssl/openssl/pull/30557
   "re-constructorize the cpuid stuff, but fix riscv to not depend
   on BIO_snprintf."

3.6.2 NEWS.md includes the following:
 * CVE-2026-2673, CVE-2026-28386, CVE-2026-28387, CVE-2026-28388,
   CVE-2026-28389, CVE-2026-28390, CVE-2026-31789, CVE-2026-31790

Signed-off-by: Eugene Syromiatnikov <esyr@openssl.org>
Reviewed-by: Tomas Mraz <tomas@openssl.foundation>
Reviewed-by: Paul Dale <paul.dale@oracle.com>
MergeDate: Sat Apr 11 18:51:42 2026
(Merged from https://github.com/openssl/openssl/pull/30720)