Use any[] for untyped array instead of []

Fixes a typescript compiler error: "A tuple type element list cannot be empty"

Author: Xenoage

types/index.d.ts

@@ -1331,7 +1331,7 @@ declare module "jspdf" {
   }
 
   export interface jsPDFAPI {
-    events: [];
+    events: any[];
   }
 
   export default jsPDF;