CodePipeline Doc Update Encryption Key (#3190)

* updating codepipeline encryption key documentation

* fixing the missing bracket

website/docs/r/codepipeline.markdown

@@ -71,13 +71,21 @@ resource "aws_iam_role_policy" "codepipeline_policy" {
 EOF
 }
 
+data "aws_kms_alias" "s3kmskey" {
+  name = "alias/myKmsKey"
+}
+
 resource "aws_codepipeline" "foo" {
   name     = "tf-test-pipeline"
   role_arn = "${aws_iam_role.foo.arn}"
 
   artifact_store {
     location = "${aws_s3_bucket.foo.bucket}"
     type     = "S3"
+    encryption_key {
+      id   = "${data.aws_kms_alias.s3kmskey.arn}"
+      type = "KMS"
+    }
   }
 
   stage {
@@ -132,8 +140,12 @@ An `artifact_store` block supports the following arguments:
 
 * `location` - (Required) The location where AWS CodePipeline stores artifacts for a pipeline, such as an S3 bucket.
 * `type` - (Required) The type of the artifact store, such as Amazon S3
-* `encryption_key` - (Optional) The encryption key AWS CodePipeline uses to encrypt the data in the artifact store, such as an AWS Key Management Service (AWS KMS) key. If you don't specify a key, AWS CodePipeline uses the default key for Amazon Simple Storage Service (Amazon S3).
+* `encryption_key` - (Optional) The encryption key block AWS CodePipeline uses to encrypt the data in the artifact store, such as an AWS Key Management Service (AWS KMS) key. If you don't specify a key, AWS CodePipeline uses the default key for Amazon Simple Storage Service (Amazon S3). An `encryption_key` block is documented below.
+
+A `encryption_key` block supports the following arguments:
 
+* `id` - (Required) The KMS key ARN or ID
+* `type` - (Required) The type of key; currently only `KMS` is supported
 
 A `stage` block supports the following arguments: