message: Fix the clang Dockerfile
diff: -FROM ubuntu:18.04
  +FROM ubuntu:20.04
  # This forces dpkg not to call sync() after package extraction and speeds up install
  RUN echo "force-unsafe-io" > /etc/dpkg/dpkg.cfg.d/02apt-speedup
  @@ -9,6 +9,8 @@ RUN echo "Acquire::http {No-Cache=True;};" > /etc/apt/apt.conf.d/no-cache
  # Install clang and everything needed to build core
  RUN apt-get update \
  && apt-get install -y \
  + clang-11 \
  + clang-format-11 \
  libcurl4-openssl-dev \
  libprocps-dev \
  libuv1-dev \
  @@ -18,18 +20,6 @@ RUN apt-get update \
  wget \
  zlib1g-dev
  -# Setup the LLVM repository
  -RUN echo deb http://apt.llvm.org/bionic/ llvm-toolchain-bionic-11 main > /etc/apt/sources.list.d/clang.list
  -# Download the GBG key to use the LLVM repo
  -ADD https://apt.llvm.org/llvm-snapshot.gpg.key /tmp/llvm.key
  -
  -# Add the key
  -RUN apt-key add /tmp/llvm.key
  -
  -RUN apt-get update \
  - && apt-get install -y clang-11 clang-format-11 \
  - && rm -rf /var/lib/apt/lists/*
  -
  # Make clang the default compiler
  ENV CC clang
  ENV CXX clang++
  @@ -39,7 +29,7 @@ RUN ln -s /usr/bin/clang-11 /usr/bin/clang \
  && ln -s /usr/bin/git-clang-format-11 /usr/bin/git-clang-format
  RUN cd /opt \
  - && wget -nv https://cmake.org/files/v3.15/cmake-3.15.2-Linux-x86_64.tar.gz \
  - && tar zxf cmake-3.15.2-Linux-x86_64.tar.gz
  + && wget -nv https://github.com/Kitware/CMake/releases/download/v3.21.3/cmake-3.21.3-linux-x86_64.tar.gz \
  + && tar zxf cmake-3.21.3-linux-x86_64.tar.gz
  -ENV PATH "/opt/cmake-3.15.2-Linux-x86_64/bin:$PATH"
  +ENV PATH "/opt/cmake-3.21.3-linux-x86_64/bin:$PATH"
  