download: build-from-source: require cmake 3.13

Author: thomastrapp

jekyll/_includes/download/build-from-source.html

@@ -8,7 +8,7 @@ <h3>On a Debian-based distribution</h3>
     </p>
     <ul class="ui list">
       <li>g++ ≥7.3 or clang ≥6.0</li>
-      <li>cmake ≥3.8</li>
+      <li>cmake ≥3.13</li>
       <li>libboost-dev ≥1.55</li>
       <li>libboost-regex-dev ≥1.55</li>
       <li>libboost-program-options-dev ≥1.55</li>
@@ -23,7 +23,7 @@ <h3>On other systems (*nix, OS X, Win)</h3>
     </p>
     <ul class="ui list">
       <li>g++ ≥7.3 or clang ≥6.0</li>
-      <li><a href="https://cmake.org/">CMake</a> ≥3.8</li>
+      <li><a href="https://cmake.org/">CMake</a> ≥3.13</li>
       <li><a href="http://www.boost.org/">Boost</a> ≥1.55,
           specifically Boost.Regex and Boost.Program_options</li>
       <li>libtool and autoconf for building