Upgrade to Jetty 9.4.44.v20210927

Closes gh-28320

Author: snicoll

spring-boot-project/spring-boot-dependencies/build.gradle

@@ -888,7 +888,7 @@ bom {
 			]
 		}
 	}
-	library("Jetty", "9.4.43.v20210629") {
+	library("Jetty", "9.4.44.v20210927") {
 		prohibit("[10.0.0-alpha0,)") {
 			because "it requires Java 11"
 		}