PublicKeyCertificateFormat(value)The supported formats for the public key.
Values:
UNSPECIFIED_PUBLIC_KEY_CERTIFICATE_FORMAT (0):
The format has not been specified. This is an
invalid default value and must not be used.
X509_CERTIFICATE_PEM (1):
An X.509v3 certificate
(RFC5280 <https://www.ietf.org/rfc/rfc5280.txt>__),
encoded in base64, and wrapped by
-----BEGIN CERTIFICATE----- and
-----END CERTIFICATE-----.