ci/Containerfile: add glibc-gconv-modules-extra to build container

The Buildroot image generation step uses mtools to populate a VFAT boot
image. In the container mcopy was failing with:

  Error converting to codepage 850

The container was missing the glibc gconv modules that provide CP850
conversion support. Add glibc-gconv-modules-extra so mtools can handle
DOS codepage conversion correctly during image generation.

Signed-off-by: Ozan Durgut <ozan.durgut@analog.com>

Author: ozan956

ci/Containerfile

@@ -18,7 +18,7 @@ RUN bash ./gh-actions-runner.sh ; rm ./gh-actions-runner.sh
 
 # Install packages required by Buildroot:
 # https://buildroot.org/downloads/manual/manual.html#requirement-mandatory
-RUN zypper install -y --no-recommends gcc gcc-c++ make glibc-devel \
+RUN zypper install -y --no-recommends gcc gcc-c++ make glibc-devel glibc-gconv-modules-extra \
     libstdc++-devel binutils ccache git wget rsync bc unzip cpio file which \
     sed diffutils bash patch gzip bzip2 perl tar findutils gawk ncurses-devel