west.yml: Add zscilib reference

Adds a reference to zscilib, now that it's available under
zephyrproject-rtos/zscilib.

Signed-off-by: Kevin Townsend <kevin@ktownsend.com>
diff --git a/west.yml b/west.yml
index d59033c..b66a1f9 100644
--- a/west.yml
+++ b/west.yml
@@ -235,6 +235,9 @@
       path: modules/tee/tf-m/psa-arch-tests
       groups:
         - tee
+    - name: zscilib
+      path: modules/lib/zscilib
+      revision: 12bfe3f0a9fcbfe3edab7eabc9678b6c62875d34
 
   group-filter:
     - -ci