added changelog

.changelog/19499.txt

@@ -0,0 +1,3 @@
+```release-note:feature
+acl: add policy bindtype to binding rules.
+```

agent/consul/auth/binder.go

@@ -204,7 +204,7 @@ func IsValidBindingRule(bindType, bindName string, bindVars *structs.ACLTemplate
 			return fmt.Errorf("failed to validate bindType %q: %w", bindType, err)
 		}
 	default:
-		return fmt.Errorf("Invalid Binding Rule: unknown BindType %q", bindType)
+		return fmt.Errorf("invalid Binding Rule: unknown BindType %q", bindType)
 	}
 
 	return nil