The function was renamed in OpenSSL 3.0 due to the change of the
lifetime of EVP_MD objects. They are no longer necessarily statically
allocated and can be reference-counted -- when an EVP_MD_CTX is free'd,
the associated EVP_MD can also become inaccessible.

Currently Ruby/OpenSSL only handles builtin algorithms, so no special
handling is needed except for adapting to the rename.

https://github.com/ruby/openssl/commit/0a253027e6