Fix python build --mem-heap document (#3185)

`--heap-size` has been renamed to `--mem-heap`
JerryScript-DCO-1.0-Signed-off-by: legendecas [email protected]

Author: legendecas

docs/01.CONFIGURATION.md

@@ -194,7 +194,7 @@ The default value is 512.
 |---------|----------------------------------------------|
 | C:      | `-DJERRY_GLOBAL_HEAP_SIZE=(int)`             |
 | CMake:  | `--DJERRY_GLOBAL_HEAP_SIZE=(int)`            |
-| Python: | `--heap-size=(int)`                          |
+| Python: | `--mem-heap=(int)`                           |
 
 ### Garbage collection limit