Correct spelling of Python variable in CMake (#1319)

Pyhton -> Python

Signed-off-by: Michael Carroll <[email protected]>

Author: mjcarroll

sdf/1.5/CMakeLists.txt

@@ -67,7 +67,7 @@ foreach(FIL ${sdfs})
 
   add_custom_command(
     OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/${FIL_WE}.xsd"
-    COMMAND ${Pyhton3_EXECUTABLE} ${CMAKE_SOURCE_DIR}/tools/xmlschema.py
+    COMMAND ${Python3_EXECUTABLE} ${CMAKE_SOURCE_DIR}/tools/xmlschema.py
     ARGS --sdf-dir ${CMAKE_CURRENT_SOURCE_DIR} --input-file ${ABS_FIL} --output-dir ${CMAKE_CURRENT_BINARY_DIR}
     DEPENDS ${ABS_FIL}
     COMMENT "Running xml schema compiler on ${FIL}"