message: [travis gbc] Use latest stack
diff: @@ -25,9 +25,8 @@ RUN apt-get -y install \
  cmake \
  golang
  -# Components for Haskell
  -RUN apt-get -y install \
  - haskell-stack
  +# Components for Haskell. See https://docs.haskellstack.org/en/stable/install_and_upgrade/#linux
  +RUN wget -qO- https://get.haskellstack.org/ | sh
  # Components for C#. See http://www.mono-project.com/download/#download-lin
  RUN apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys 3FA7E0328081BFF6A14DA29AA6A19B38D3D831EF && \
  