Support certificates as public keys

[qianxi0410]

When I use the certificate-private key mode, I have the certificate as the public key, but when I use public key(certificate) parsing, the program keeps telling me that the key format is not correct.

And I just replace the format as follows, and it works fine:

before:

-----BEGIN CERTIFICATE-----
...
-----END CERTIFICATE-----

-----BEGIN PRIVATE KEY-----
...
-----END PRIVATE KEY-----

after:

-----BEGIN PUBLIC KEY-----
...
-----END PUBLIC KEY-----

-----BEGIN PRIVATE KEY-----
...
-----END PRIVATE KEY-----

[jetaggart]

I have this issue as well. Firebase has the certificate format: https://www.googleapis.com/robot/v1/metadata/x509/securetoken@system.gserviceaccount.com

[Alexey-N-Chernyshov]

Done, may be closed.