fix go evt problem

Go vet reported a problem with the interface of WriteTo returning an
int.

  Line 13: method WriteTo(stream io.Writer) (int, error)
        should have signature WriteTo(io.Writer) (int64, error)

To fix that problem, the interface was changed to return io.WriterTo,
which uses int64 for return values.

1 files changed, 2 insertions, 1 deletions

diff --git a/types.go b/types.go
index 43150f9..08c42d8 100644
--- a/types.go
+++ b/types.go
@@ -16,6 +16,7 @@ package pki
 
 import (
   "crypto"
+  "io"
 )
 
 // This label is used as the type in the pem encoding of public keys.
@@ -47,6 +48,6 @@ type (
   // in the pem format. The result can then be written to any structure
   // implementing the io.Writer interface.
   Pemmer interface {
-    MarshalPem() (marshalledPemBlock, error)
+    MarshalPem() (io.WriterTo, error)
   }
 )