README: Mention list archive on lore.kernel.org

lore.kernel.org uses public-inbox, which has a much nicer front-end for
viewing and searching and the archive can be cloned as a git repo.

Change-Id: I2568b806f212fc1c0895c26c67d20fae59b2314e
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
diff --git a/README.md b/README.md
index 62db3c3..204023d 100644
--- a/README.md
+++ b/README.md
@@ -12,6 +12,7 @@
 ## Contact
 
 - Mail: openbmc@lists.ozlabs.org https://lists.ozlabs.org/listinfo/openbmc
+- List Archive: https://lore.kernel.org/openbmc/
 - Discord: https://discord.gg/69Km47zH98
 - IRC: #openbmc on freenode.net