esp-idf: update to v4.2

redchenjs · redchenjs · commit 15ec9a2d80d9 · 2021-09-03T00:39:53.000+08:00
diff --git a/esp-idf b/esp-idf
@@ -1 +1 @@
-Subproject commit 7ab8f793ca5b026f37ae812bcc103e3aa698d164
+Subproject commit c40f2590bf759ff60ef122afa79b4ec04e7633d2
