Build(deps): bump io.undertow:undertow-core

Bumps [io.undertow:undertow-core](https://github.com/undertow-io/undertow) from 2.3.20.Final to 2.3.21.Final.
- [Release notes](https://github.com/undertow-io/undertow/releases)
- [Commits](undertow-io/undertow@2.3.20.Final...2.3.21.Final)

---
updated-dependencies:
- dependency-name: io.undertow:undertow-core
  dependency-version: 2.3.21.Final
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

frameworks/Java/light-java/pom.xml

@@ -25,7 +25,7 @@
         <maven.compiler.target>11</maven.compiler.target>
         <version.light-4j>2.0.1</version.light-4j>
         <version.logback>1.3.12</version.logback>
-        <version.undertow>2.3.20.Final</version.undertow>
+        <version.undertow>2.3.21.Final</version.undertow>
         <version.hikaricp>3.3.1</version.hikaricp>
         <version.mysql>8.0.28</version.mysql>
         <version.postgres>42.7.2</version.postgres>