use useradd instead of adduser

Avoid this error:

  adduser: No UID/GID pair is available in the range 1000-59999 (FIRST_UID - LAST_UID).

Dockerfile

-FROM debian:12
+FROM debian:bookworm-slim
 
 RUN apt-get update \
     && apt-get install -y ca-certificates \
@@ -31,7 +31,7 @@ RUN apt-get update \
     && rm -rf /var/lib/apt/lists/*
 
 # gluon build fails when running as root
-RUN adduser --quiet --disabled-login --gecos '' build
+RUN useradd -m -d /build -u 100 -g 100 -o build
 USER build:build
 # workaround for fatal: detected dubious ownership in repository at '/builds/firmware/site-ffs'
 # https://gitlab.com/gitlab-org/gitlab-runner/-/issues/29022