Dev Container build fails

[markusressel]

Following the instructions in the README via CLion, the container build fails:

=> ERROR [ 2/12] RUN apt-get update &&     apt-get install -y --no-install-recommends         curl         libfreetype6-dev         bash-completion  1.1s
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 > [ 2/12] RUN apt-get update &&     apt-get install -y --no-install-recommends         curl         libfreetype6-dev         bash-completion         libsdl1.2debian         libfdt1         libpixman-1-0         libglib2.0-dev         vim         zsh         git         wget         firefox-esr         python-virtualenv &&     apt-get clean &&     rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*:
0.842 Ign:1 http://deb.debian.org/debian buster InRelease
0.842 Ign:2 http://security.debian.org/debian-security buster/updates InRelease
0.871 Err:3 http://security.debian.org/debian-security buster/updates Release
0.871   404  Not Found [IP: 151.101.194.132 80]
0.873 Ign:4 http://deb.debian.org/debian buster-updates InRelease
0.900 Err:5 http://deb.debian.org/debian buster Release
0.900   404  Not Found [IP: 151.101.194.132 80]
0.923 Err:6 http://deb.debian.org/debian buster-updates Release
0.923   404  Not Found [IP: 151.101.194.132 80]
0.927 Reading package lists...
0.936 E: The repository 'http://security.debian.org/debian-security buster/updates Release' does not have a Release file.
0.936 E: The repository 'http://deb.debian.org/debian buster Release' does not have a Release file.
0.936 E: The repository 'http://deb.debian.org/debian buster-updates Release' does not have a Release file.
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Dockerfile:19