Fix lint

Author: microbit-grace

src/ihex.ts

@@ -315,10 +315,11 @@ function blockEndRecord(padBytesLen: number): string {
     case 0x0c:
       // The most common padding, when a block has 10 full (0x10) Data records
       return ':0C00000BFFFFFFFFFFFFFFFFFFFFFFFFF5';
-    default:
+    default: {
       // Input sanitation will be done in createRecord, no need to do it here too
       const recordData = new Uint8Array(padBytesLen).fill(0xff);
       return createRecord(0, RecordType.BlockEnd, recordData);
+    }
   }
 }