Update zmk project revision to v0.3

Author: HeeTuic

config/west.yml

@@ -7,7 +7,7 @@ manifest:
   projects:
     - name: zmk
       remote: zmkfirmware
-      revision: main
+      revision: v0.3
       import: app/west.yml
     - name: zmk-pmw3610-driver
       remote: DoctorWangWang