Update localversion-st, tree is up-to-date with 5.10.258.

Bumped localversion to -st18.

Signed-off-by: Ulrich Hecht <uli@kernel.org>
diff --git a/localversion-st b/localversion-st
index e817cab..b2de37a 100644
--- a/localversion-st
+++ b/localversion-st
@@ -1 +1 @@
--st17
+-st18