kms: regen gapic; removes alpha notice

Change-Id: I38dbe356058e28c4effdfc910229e72db1adc586
Reviewed-on: https://code-review.googlesource.com/30590
Reviewed-by: Jonathan Amsterdam <jba@google.com>
Reviewed-by: kokoro <noreply+kokoro@google.com>
diff --git a/kms/apiv1/doc.go b/kms/apiv1/doc.go
index 7afa683..110e109 100644
--- a/kms/apiv1/doc.go
+++ b/kms/apiv1/doc.go
@@ -16,8 +16,7 @@
 
 // Package kms is an auto-generated package for the
 // Google Cloud Key Management Service (KMS) API.
-//
-//   NOTE: This package is in alpha. It is not stable, and is likely to change.
+
 //
 // Manages encryption for your cloud services the same way you do
 // on-premises.