Set/document min version of cmake needed.

3.21.0 min for the new ctest option --output-junit.

CDashConfScript.cmake

-cmake_minimum_required(VERSION 3.0.2)
+cmake_minimum_required(VERSION 3.21.0)
 
 
 set (CTEST_SOURCE_DIRECTORY "${CTEST_SCRIPT_DIRECTORY}")

README.md

@@ -31,6 +31,7 @@ matio own dependencies, as hdf5 and zlib. matio dependency can be disabled throu
 (there is a constraint on the gcc compiler version depending on the used Matlab version,
 the CMake script indicate if the match is not appropriate).
 - libxml2 (Optional, needed with CMake ``BUILD_READ_XML_FILE``).
+- CMake >= 3.21.0
 - TODO: other?