Use const instead of let

Author: yaph

src/ts/notes.ts

@@ -1,6 +1,6 @@
 import { Note as TonalNote } from '@tonaljs/tonal';
 
-let chromatic_scale = ['A', 'A#', 'B', 'C', 'C#', 'D', 'D#', 'E', 'F', 'F#', 'G', 'G#'];
+const chromatic_scale = ['A', 'A#', 'B', 'C', 'C#', 'D', 'D#', 'E', 'F', 'F#', 'G', 'G#'];
 
 
 /**