Change slot_uri for literal (#357)

Made a mistake here #356 Thanks for catching @hrshdhgd

Author: matentzn

src/sssom_schema/schema/sssom_schema.yaml

@@ -128,7 +128,7 @@ slots:
     required: true
     mappings:
     - owl:annotatedSource
-    slot_uri: owl:annotatedSource
+    slot_uri: owl:annotatedTarget
     examples:
       - value: "Alzheimer"
         description: A string referring to some thing.