CI: Move to Ubuntu 25.04 for i686-unkown-linux-gnu

Author: Marcondiro

ci/docker/i686-unknown-linux-gnu/Dockerfile

@@ -1,9 +1,6 @@
-FROM ubuntu:23.10
+FROM ubuntu:25.04
 
-# FIXME(time): we are using an EOL release because 24.04 changes to 64-bit time
-RUN sed -i -E 's/(archive|security)\.ubuntu\.com/old-releases.ubuntu.com/g' \
-        /etc/apt/sources.list && \
-    apt-get update && apt-get install -y --no-install-recommends \
+RUN apt-get update && apt-get install -y --no-install-recommends \
         ca-certificates \
         gcc-multilib \
         libc6-dev