Support cosign key type

[colek42]

➜  kubectl git:(master) ✗ cosign generate-key-pair
Enter password for private key: 
Enter password for private key again: 
File cosign.key already exists. Overwrite (y/n)? y
Private key written to cosign.key
Public key written to cosign.pub
➜  kubectl git:(master) ✗ cat cosign.key          
-----BEGIN ENCRYPTED COSIGN PRIVATE KEY-----
REDACTED
TlIrY3c0VGs0b0lSaHNwam5hcWVuWlFHcHc9PSJ9
-----END ENCRYPTED COSIGN PRIVATE KEY-----

[developer-guy]

can you explain a bit more, please? Thx