Update guessing game usage of rand

rustbook/guessing_game/src/main.rs

@@ -5,7 +5,7 @@ use std::io;
 fn main() {
     println!("Guess the number!");
 
-    let secret_number = rand::thread_rng().gen_range(1, 101);
+    let secret_number = rand::thread_rng().gen_range(1..=100);
 
     loop {
         println!("Please input your guess.");