README.md: Point to simtrace mailing list

SIM card related topics are best kept there and not on openbsc.

Change-Id: I0dedd2ed0ab07c6020f9d30857654c5600c53814
diff --git a/README.md b/README.md
index 7801283..7d69db1 100644
--- a/README.md
+++ b/README.md
@@ -127,9 +127,9 @@
 ------------
 
 There is no separate mailing list for this project. However,
-discussions related to pysim-prog are happening on the
-<openbsc@lists.osmocom.org> mailing list, please see
-<https://lists.osmocom.org/mailman/listinfo/openbsc> for subscription
+discussions related to pySim are happening on the simtrace
+<simtrace@lists.osmocom.org> mailing list, please see
+<https://lists.osmocom.org/mailman/listinfo/simtrace> for subscription
 options and the list archive.
 
 Please observe the [Osmocom Mailing List