OpenSSL 3+ deprecates the SHA256_Init, SHA256_Update, and SHA256_Final
functions, leading to errors when building with `DEVELOPER=1'.
Use the newer EVP_* API with OpenSSL 3+ despite being more
error-prone and less efficient due to heap allocations.
Signed-off-by: Eric Wong <e@80x24.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>