Upgrade to Undertow 2.0.28.Final

Closes gh-19131

Author: snicoll

spring-boot-project/spring-boot-dependencies/pom.xml

@@ -209,7 +209,7 @@
 		<thymeleaf-extras-java8time.version>3.0.4.RELEASE</thymeleaf-extras-java8time.version>
 		<tomcat.version>9.0.27</tomcat.version>
 		<unboundid-ldapsdk.version>4.0.12</unboundid-ldapsdk.version>
-		<undertow.version>2.0.27.Final</undertow.version>
+		<undertow.version>2.0.28.Final</undertow.version>
 		<webjars-hal-browser.version>3325375</webjars-hal-browser.version>
 		<webjars-locator-core.version>0.41</webjars-locator-core.version>
 		<wsdl4j.version>1.6.3</wsdl4j.version>