[changelog] Add entry about Python version requirements of bindings

CHANGELOG.md

@@ -51,6 +51,10 @@ In order to build the DUNE core modules you need at least the following software
 
 - Do not overwrite the `add_test` cmake function with an error message.
 
+- The Python bindings require at least Python 3.6 or higher. This is now enforced
+  through CMake. The bindings are disabled prompting the user with a message containing
+  the reason, if no suitable Python version is found.
+
 ## Deprecations and removals
 
 - The deprecated header `dune/common/function.hh` has been removed. Use C++ function