Update README.md to include video overview and remove unused method

- Added a video link for a quick overview of the Jesse framework to enhance user understanding.
- Removed the `should_cancel_entry` method from the `SMACrossover` strategy class as it was unnecessary, streamlining the code.

README.md

@@ -21,6 +21,8 @@ Algo-trading was 😵‍💫, we made it 🤩
 Jesse is an advanced crypto trading framework that aims to **simplify** **researching** and defining **YOUR OWN trading strategies** for backtesting, optimizing, and live trading.
 
 ## What is Jesse?
+Watch this video to get a quick overview of Jesse:
+
 [![Jesse Overview](https://img.youtube.com/vi/0EqN3OOqeJM/0.jpg)](https://www.youtube.com/watch?v=0EqN3OOqeJM)
 
 ## Why Jesse?
@@ -65,9 +67,6 @@ class SMACrossover(Strategy):
         # Fast SMA below Slow SMA
         return self.fast_sma < self.slow_sma
 
-    def should_cancel_entry(self) -> bool:
-        return False
-
     def go_long(self):
         # Open long position and use entire balance to buy
         qty = utils.size_to_qty(self.balance, self.price, fee_rate=self.fee_rate)