Bump org.eclipse.jetty:jetty-server in /geowebcache

Bumps org.eclipse.jetty:jetty-server from 9.4.55.v20240627 to 9.4.56.v20240826.

---
updated-dependencies:
- dependency-name: org.eclipse.jetty:jetty-server
  dependency-version: 9.4.56.v20240826
  dependency-type: direct:production
...

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

Author: dependabot[bot]

geowebcache/pom.xml

@@ -85,7 +85,7 @@
     <pom.fmt.skip>${spotless.apply.skip}</pom.fmt.skip>
     <jackson.version>2.18.2</jackson.version>
     <jackson.databind.version>${jackson.version}</jackson.databind.version>
-    <jetty.version>9.4.55.v20240627</jetty.version>
+    <jetty.version>9.4.56.v20240826</jetty.version>
     <errorProneFlags></errorProneFlags>
     <errorProne.version>2.24.1</errorProne.version>
     <javac.version>9+181-r4173-1</javac.version>