open62541 API Change - X.509 authentication

The API has been changed, needs to be fixed like here:
open62541/open62541@2c87f1e
In this line:

Line 102 in dab4550

    
           status = UA_AccessControl_default(pConfig, true, &pConfig->securityPolicies[pConfig->securityPoliciesSize - 1].policyUri, users.size(), &users[0]);

Originally posted by @ccvca in #458 (comment)