mbed detect: add DISCO_H745I

Author: jeromecoutant

src/mbed_os_tools/detect/platform_database.py

@@ -180,6 +180,7 @@
         u"0839": u"NUCLEO_WB55RG",
         u"0840": u"B96B_F446VE",
         u"0841": u"NUCLEO_G474RE",
+        u"0847": u"DISCO_H745I",
         u"0854": u"NUCLEO_L552ZE_Q",
         u"0855": u"DISCO_L562QE",
         u"0879": u"NUCLEO_F756ZG",