fix(test1): renamed function name to snake case

closes #180

exercises/test1.rs

@@ -13,8 +13,8 @@
 // Don't modify this function!
 #[test]
 fn verify_test() {
-    let price1 = calculateprice(55);
-    let price2 = calculateprice(40);
+    let price1 = calculate_price(55);
+    let price2 = calculate_price(40);
 
     assert_eq!(price1, 55);
     assert_eq!(price2, 80);