ci: upgrade base Docker image to eclipse-temurin:21-jre-noble (#450)

sfreudenthaler · web-flow · commit 85ebf002409f · 2026-03-17T13:53:02.000-04:00
Upgraded base image from jammy to noble (24.04 LTS) for security
patches.
diff --git a/Dockerfile.test b/Dockerfile.test
@@ -0,0 +1 @@
+FROM eclipse-temurin:21-jre-noble
