package/libcurl: security bump to version 7.71.0
CVE-2020-8177: curl overwrite local file with -J.
CVE-2020-8169: Partial password leak over DNS on HTTP redirect.
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>