[handbook] Bump the required CMake version to 3.14.

doc/handbook/0_dumux-handbook.tex

@@ -48,6 +48,7 @@
 \definecolor{dumuxBlue}{HTML}{0C73CF}
 \newcommand{\DuneVersion}{2.9}
 \newcommand{\DuneOldVersion}{2.8}
+\newcommand{\CMakeVersion}{3.14}
 
 % styles
 \newcommand{\nextline}{\par\phantom{a}\vspace*{0.1\textwidth}}

doc/handbook/2_quickinstall.tex

@@ -3,7 +3,7 @@ For this quick start guide the following software packages are required:
 \begin{itemize}
 \item GitLab client
 \item A standard-compliant C++17 compiler supporting the common supported C++11/C++14/C++17 feature set of GCC 9.3 and Clang 10
-\item CMake 3.13 or newer
+\item CMake \CMakeVersion{} or newer
 \item pkg-config
 \item ParaView (to visualize the results)
 \end{itemize}