ucert: update to version 2019-12-19

ucert: update to version 2019-12-19

14a279411cff fix certificate blob parsing vulnerability by using blob_parse_untrusted
19a7225ac018 fix leaking memory in cert_dump_blob
9dba44ddd4f5 fix possibly garbage value returned in cert_process_revoker
4462ff9dedfa add cram based unit tests
5fe64b5606aa cmake: split usign bits into static library
5d7626a2b6d8 cmake: reindent the file
e284ed941972 cmake: enable hardening compiler flags and fix the reported issues
7e5390666347 add initial GitLab CI support
fa0bf4ef45b1 cmake: add proper include and library dependencies

Signed-off-by: Petr Štetiar <ynezz@true.cz>
(cherry picked from commit 2544cb1ba377149a8663c7ac4a625d5399993e33)