Add branch for telegrambot binary without the required feature

src/bin/telegrambot.rs

@@ -1,6 +1,9 @@
-#![cfg(feature = "telegram")]
-
+#[cfg(not(feature = "telegram"))]
+fn main() {
+    println!("The `telegram` feature was not included on compilation, therefore this binary is not available.")
+}
 
+#[cfg(feature = "telegram")]
 fn main() {
     println!("Hello telegram world!")
-}
+}