Bump AppImage to Ubuntu 20.04

18.04 is out of security support, and cmake for 18.04 is no longer
available via kitware's debian repository (or at least fetching it
failed for one build).

1 files changed, 4 insertions, 19 deletions

diff --git a/appimage/Dockerfile b/appimage/Dockerfile
index da0b8b72..c1914144 100644
--- a/appimage/Dockerfile
+++ b/appimage/Dockerfile
@@ -1,28 +1,13 @@
-FROM ubuntu:18.04 as start
+FROM ubuntu:20.04
 ENV DEBIAN_FRONTEND=noninteractive
 RUN apt-get update
 RUN apt-get -y install screen git sudo \
-    build-essential pkg-config \
+    build-essential pkg-config cmake \
     zlib1g-dev libjpeg-dev libgnutls28-dev \
     python3-pip texlive-latex-extra latexmk \
-    inkscape imagemagick busybox-static wget fuse
-
-# Until we move to ubuntu:20.04, we need a newer cmake. After 20.04,
-# we can remove this and add cmake to the install above.
-RUN apt-get -y install software-properties-common wget
-RUN wget -O /etc/apt/trusted.gpg.d/kitware.asc \
-    https://apt.kitware.com/keys/kitware-archive-latest.asc
-RUN apt-add-repository 'deb https://apt.kitware.com/ubuntu/ bionic main'
-RUN apt-get update
-RUN apt-get -y install cmake
-# End cmake
-
-RUN apt-get clean && rm -rf /var/lib/apt/lists/*
-
+    inkscape imagemagick busybox-static wget fuse && \
+    apt-get clean && rm -rf /var/lib/apt/lists/*
 RUN pip3 install sphinx sphinx_rtd_theme
-
-FROM ubuntu:18.04 as run
-COPY --from=start / /
 COPY entrypoint /entrypoint
 RUN chmod +x /entrypoint
 ENTRYPOINT [ "/entrypoint" ]