package/libcurl: bump version to 8.15.0

Upstream removed optional BearSSL support:
https://github.com/curl/curl/commit/08a3e8e19a59d1530bfb208e187ac7c34c978dfd

Changelog: https://curl.se/ch/8.15.0.html

Signed-off-by: Bernd Kuhls <bernd@kuhls.net>
Signed-off-by: Julien Olivain <ju.o@free.fr>
4 files changed