update libsrtp to version 2.7.0
rename libsrtp branch https://gitlab.linphone.org/BC/public/external/srtp/-/tree/update/v2.7.0?ref_type=heads to bc on merge.
Edited by johan
rename libsrtp branch https://gitlab.linphone.org/BC/public/external/srtp/-/tree/update/v2.7.0?ref_type=heads to bc on merge.