document cmake 3.22.1 requirement

Signed-off-by: Steve Peters <[email protected]>

tutorials/02_installation.md

@@ -189,6 +189,8 @@ echo "export LD_LIBRARY_PATH=<install_path>/local/lib:$LD_LIBRARY_PATH" >> ~/.ba
 If you want to build Python bindings separately from the main gz-transport library
 (for example if you want to build Python bindings for multiple versions of Python),
 you can invoke cmake on the `python` folder instead of the root folder.
+This requires cmake version 3.22.1 due to the use of a `CMAKE_REQUIRE_FIND_PACKAGE_*`
+variable, which is newer than the minimum required version of cmake for gz-transport13.
 Specify the path to the python executable with which you wish to build bindings
 in the `Python3_EXECUTABLE` cmake variable.
 Specify the install path for the bindings in the `CMAKE_INSTALL_PREFIX`