message: Use centos-7 with building Linux release
diff: -FROM centos:6
  +FROM centos:7
  # Install EPEL & devtoolset
  -# On CentOS6, there is a bug with OverlayFS and Docker. It is needed to touch
  -# /var/lib/rpm/* in order to work around this issue.
  -# Link: https://github.com/docker/docker/issues/10180
  -RUN touch /var/lib/rpm/* \
  - && yum -y install \
  +RUN yum -y install \
  epel-release \
  centos-release-scl-rh
  @@ -15,9 +11,11 @@ RUN yum -y install \
  devtoolset-8-gcc \
  devtoolset-8-gcc-c++ \
  git \
  + ninja-build \
  unzip \
  wget \
  which \
  + zlib-devel \
  && yum clean all
  # Install CMake
  @@ -26,10 +24,3 @@ RUN cd /opt \
  && tar zxf cmake-3.15.2-Linux-x86_64.tar.gz
  ENV PATH "/opt/cmake-3.15.2-Linux-x86_64/bin:$PATH"
  -
  -# Install ninja
  -RUN git clone https://github.com/ninja-build/ninja.git \
  - && cd ninja \
  - && scl enable devtoolset-8 -- cmake -B build-cmake \
  - && cmake --build build-cmake \
  - && mv build-cmake/ninja /usr/bin
  