Update gerrit docker image to 3.8.1-almalinux9

Update gerrit docker images in examples to the latest stable-3.8
version

Change-Id: Idb02bc75fb6901344477a37c09d1db3cd754cc92
diff --git a/example-setup/broker/Dockerfile b/example-setup/broker/Dockerfile
index 67eecd9..d615273 100644
--- a/example-setup/broker/Dockerfile
+++ b/example-setup/broker/Dockerfile
@@ -1,4 +1,4 @@
-FROM gerritcodereview/gerrit:3.7.2-almalinux8
+FROM gerritcodereview/gerrit:3.8.1-almalinux9
 
 USER root
 
diff --git a/example-setup/http/Dockerfile b/example-setup/http/Dockerfile
index afadb4f..6f1d1f9 100644
--- a/example-setup/http/Dockerfile
+++ b/example-setup/http/Dockerfile
@@ -1,4 +1,4 @@
-FROM gerritcodereview/gerrit:3.7.2-almalinux8
+FROM gerritcodereview/gerrit:3.8.1-almalinux9
 
 USER root