need zlib1g-dev for libxml for nokogiri, etc, etc (#2854)

Also bumping to debian:12 for grins

Author: jamis

release/mri/Dockerfile

@@ -1,9 +1,9 @@
-FROM debian:10
+FROM debian:12
 
 ENV DEBIAN_FRONTEND=noninteractive
 
 RUN apt-get update && \
-  apt-get -y install git ruby-bundler make gcc ruby-dev
+  apt-get -y install git ruby-bundler make gcc ruby-dev zlib1g-dev
 
 WORKDIR /app