Set explicit visibility on class constants

src/MDLoanTypesSet.php

@@ -11,9 +11,9 @@
  */
 final class MDLoanTypesSet extends MDValueSet {
 
-    const DEFAULT_LOAN_TYPE = 'outgoing';
+    public const DEFAULT_LOAN_TYPE = 'outgoing';
 
-    const LOAN_TYPES = [
+    public const LOAN_TYPES = [
         'outgoing',
         'incoming',
     ];