Fix heading depth of SD card set up

Signed-off-by: Lohit Agarwalla/Application S/W Group /SRI-Delhi/Engineer/Samsung Electronics <[email protected]>

Author: alohit

docs/platform/developing/flashing-rpi.md

@@ -22,7 +22,7 @@ IoT Setup Manager supports the following operating systems:
 -   Windows 10
 -   Ubuntu 18.04 LTS and later
 
-## SD card set up
+### SD card set up
 
 The SD card must be formatted before flashing the image into it.