tools/docker: Fix CMake version

need at least 3.18

cmake/README.md

@@ -65,7 +65,8 @@ CMake as a standalone project or it can be incorporated into an existing CMake
 ## Requirement
 You'll need:
 
-* `CMake >= 3.15` (`3.18` for python support).
+* `CMake >= 3.18`.
+* A C++20 compiler (gcc 8 or above)
 
 ## Dependencies
 

makefiles/README.md

@@ -52,6 +52,7 @@ used on a wide range of platforms.
 You'll need:
 
 * `GNU Make >= 4.3`.
+* A C++20 compiler (gcc 10 or above)
 
 ## Dependencies
 

tools/docker/amd64/opensuse-leap.Dockerfile

@@ -6,12 +6,18 @@ LABEL maintainer="corentinl@google.com"
 ENV PATH=/usr/local/bin:$PATH
 RUN zypper update -y \
 && zypper install -y git gcc11 gcc11-c++ cmake \
- wget which lsb-release util-linux pkgconfig autoconf libtool zlib-devel \
+ wget which lsb-release util-linux pkgconfig autoconf libtool gzip zlib-devel \
 && zypper clean -a
 ENV CC=gcc-11 CXX=g++-11
 ENTRYPOINT ["/usr/bin/bash", "-c"]
 CMD ["/usr/bin/bash"]
 
+# Install CMake 3.21.1
+RUN wget -q "https://cmake.org/files/v3.21/cmake-3.21.1-linux-x86_64.sh" \
+&& chmod a+x cmake-3.21.1-linux-x86_64.sh \
+&& ./cmake-3.21.1-linux-x86_64.sh --prefix=/usr/local/ --skip-license \
+&& rm cmake-3.21.1-linux-x86_64.sh
+
 # Swig Install
 RUN zypper update -y \
 && zypper install -y swig \

tools/docker/amd64/ubuntu-20.04.Dockerfile

@@ -23,6 +23,12 @@ ENV CC=gcc-11 CXX=g++-11
 ENTRYPOINT ["/bin/bash", "-c"]
 CMD ["/bin/bash"]
 
+# Install CMake 3.21.1
+RUN wget -q "https://cmake.org/files/v3.21/cmake-3.21.1-linux-x86_64.sh" \
+&& chmod a+x cmake-3.21.1-linux-x86_64.sh \
+&& ./cmake-3.21.1-linux-x86_64.sh --prefix=/usr/local/ --skip-license \
+&& rm cmake-3.21.1-linux-x86_64.sh
+
 # Swig Install
 RUN apt-get update -qq \
 && apt-get install -yq swig \