update swagger pareer to 2.1.28 #1181

Job	Run time
Build Java Client JDK11 (samples/client/echo_api/java/apache-httpclient)	1m 5s
Build Java Client JDK11 (samples/client/echo_api/java/feign-gson)	56s
Build Java Client JDK11 (samples/client/echo_api/java/resteasy)	53s
Build Java Client JDK11 (samples/client/echo_api/java/resttemplate)	1m 13s
Build Java Client JDK11 (samples/client/echo_api/java/native)	1m 11s
	5m 18s

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