Updating S3 model (#1207)

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## Motivation and Context
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Updates to S3 model to match aws/aws-models#854

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aws-models/s3.json

@@ -26084,7 +26084,7 @@
             }
         },
         "com.amazonaws.s3#LifecycleRuleFilter": {
-            "type": "union",
+            "type": "structure",
             "members": {
                 "Prefix": {
                     "target": "com.amazonaws.s3#Prefix",
@@ -32311,7 +32311,7 @@
             }
         },
         "com.amazonaws.s3#ReplicationRuleFilter": {
-            "type": "union",
+            "type": "structure",
             "members": {
                 "Prefix": {
                     "target": "com.amazonaws.s3#Prefix",