I was assigned the task to renew the SSL for a client that already was renewed on GoDaddy.
openssl genrsa -des3 -out server.pass.key 2048
openssl rsa -in server.pass.key -out server.key
openssl req -nodes -new -key server.key -out server.csr
heroku addons:add ssl:endpoint
heroku certs:add server.crt server.key