add Ep.4 video

Author: ryanRfox

intermediate-en/README.md

@@ -9,8 +9,8 @@ https://gitpod.io/#https://github.com/algorand-devrel/bootcamp
 ## Video Recordings
 Will be posted after each of the four sessions
 
-- Episode #1 [State Storage](https://youtu.be/FDAi6kHg-Zs)
-- Episode #2 [User-Defined Data Types](https://youtu.be/6nVIsJhveY8)
+- Episode #1 [State Storage (Global & Local)](https://youtu.be/FDAi6kHg-Zs)
+- Episode #2 [Box Storage & User-Defined Data Types](https://youtu.be/6nVIsJhveY8)
 - Episode #3 [Algorand Standards (ARC) for NFT, ABI and More](https://youtu.be/WiO2Y0R9x98)
-- Episode #4 [Contract Composability]
+- Episode #4 [Contract Composability](https://youtu.be/fQrCzeihp1Q)