Extracts the private key from a public-private key pair
generated by openssl::rsa_keygen()
, and encodes it in
base64 encoding.
This key can be stored in the id_rsa
private environment variable on Travis CI,
from where step_install_ssh_keys()
will pick it up to provide the CI process
with deployment rights.
encode_private_key(key)
RSA key, as returned by openssl::rsa_keygen()