🚀 use debian:bookworm as base and add bullseye to sources.list

Dockerfile

@@ -3,10 +3,11 @@
 # tier 2: more runtimes such as kotlin, java, csharp, etc..
 # tier 3: rarely used languages like brainfuck, whitespace, moo, ...
 
-FROM --platform=${BUILDPLATFORM} debian:bullseye AS tier-1
+FROM --platform=${BUILDPLATFORM} debian:bookworm AS tier-1
 
 ARG DEBIAN_FRONTEND=noninteractive
-RUN echo 'deb http://deb.debian.org/debian bookworm-backports main' >> /etc/apt/sources.list
+RUN echo 'deb http://deb.debian.org/debian bookworm-backports main\n' >> /etc/apt/sources.list
+RUN echo 'deb http://deb.debian.org/debian bullseye main' >> /etc/apt/sources.list
 RUN apt update && apt install -y gcc-13 python3.11 python2.7 clang-15 fpc pypy3 && rm -rf /var/lib/apt/lists/*
 
 FROM --platform=${BUILDPLATFORM} tier-1 AS tier-2