Switched all services to `eclipse-temurin:21-jre`

[demos/kafka/wordcount] / popular

diff --git a/popular b/popular
index 5ed4826..b5adc17 160000 (submodule)
--- a/popular
+++ b/popular
@@ -1 +1 @@
-Subproject commit 5ed4826dd2502ce8432ae9417462b771ca351e9b
+Subproject commit b5adc17bf44e22e5cdfabf7e82ab433de44d1abd