Fix PyLint "not-an-iterable" error

platformio/exception.py

@@ -19,7 +19,9 @@ class PlatformioException(Exception):
 
     def __str__(self):  # pragma: no cover
         if self.MESSAGE:
-            return self.MESSAGE.format(*self.args)
+            return self.MESSAGE.format(
+                *self.args  # pylint: disable=not-an-iterable
+            )
         return super(PlatformioException, self).__str__()