perfetto: change to yapf style

chromium style was removed in 2020 and depot_tools updated yapf past
this point so we need to switch over to the yapf style too.

Change-Id: Ic9bf8ef9a6d482a61cdeae86eb65f90e321a288f
diff --git a/.style.yapf b/.style.yapf
index de0c6a7..fdd0723 100644
--- a/.style.yapf
+++ b/.style.yapf
@@ -1,2 +1,2 @@
 [style]
-based_on_style = chromium
+based_on_style = yapf