[SC64][SW] Allow lowercase confirmation (#85)

At least one user fell for this, so we can allow lowercase to reduce
support issues

sw/tools/primer.py

@@ -781,7 +781,7 @@ def start_bring_up(self, port: str, bootloader_only: bool=False) -> None:
     Utils.log()
 
     try:
-        if (input('Type YES to continue: ') != 'YES'):
+        if (input('Type YES to continue: ').upper() != 'YES'):
             Utils.die('No confirmation received. Exiting')
         Utils.log()
     except KeyboardInterrupt: