feat: added metadata attribute

Author: Sudakatux

common/src/main/java/com/netflix/conductor/common/metadata/workflow/WorkflowDef.java

@@ -106,6 +106,9 @@ public enum TimeoutPolicy {
     @ProtoField(id = 21)
     private boolean enforceSchema = true;
 
+    @ProtoField(id = 22)
+    private Map<String,Object> metadata;
+
     public boolean isEnforceSchema() {
         return enforceSchema;
     }
@@ -366,6 +369,14 @@ public void setOutputSchema(SchemaDef outputSchema) {
         this.outputSchema = outputSchema;
     }
 
+    public Map<String, Object> getMetadata() {
+        return metadata;
+    }
+
+    public void setMetadata(Map<String, Object> metadata) {
+        this.metadata = metadata;
+    }
+
     public boolean containsType(String taskType) {
         return collectTasks().stream().anyMatch(t -> t.getType().equals(taskType));
     }