use default statement

.github/workflows/build.yml

@@ -245,10 +245,11 @@ jobs:
                     if (hm.features && hm.features.includes("keys")) {
                       return hm.requires.flatMap(i => 
                         metadata.interconnects[i].boards.flatMap(b => boardAndShield(b, hm))
-                      ) || [];
+                      );
                     }
                     break;
                   case "interconnect":
+                  default:
                     return [];
                 }
               });