Update "Learn More" (#149)

* Update "Learn More"

* Update README.md

* Update README.md

Author: stephencelis

README.md

@@ -187,7 +187,7 @@ SnapshotTesting was designed with [witness-oriented programming](https://www.poi
 
 This concept (and more) are explored thoroughly in a series of episodes on [Point-Free](https://www.pointfree.co), a video series exploring functional programming and Swift hosted by [Brandon Williams](https://github.com/mbrandonw) and [Stephen Celis](https://github.com/stephencelis).
 
-Witness-oriented programming was explored in the following episodes:
+Witness-oriented programming and the design of this library was explored in the following [Point-Free](https://www.pointfree.co) episodes:
 
   - [Episode 33](https://www.pointfree.co/episodes/ep33-protocol-witnesses-part-1): Protocol Witnesses: Part 1
   - [Episode 34](https://www.pointfree.co/episodes/ep34-protocol-witnesses-part-1): Protocol Witnesses: Part 2
@@ -196,9 +196,11 @@ Witness-oriented programming was explored in the following episodes:
   - [Episode 37](https://www.pointfree.co/episodes/ep37-protocol-oriented-library-design-part-1): Protocol-Oriented Library Design: Part 1
   - [Episode 38](https://www.pointfree.co/episodes/ep38-protocol-oriented-library-design-part-2): Protocol-Oriented Library Design: Part 2
   - [Episode 39](https://www.pointfree.co/episodes/ep39-witness-oriented-library-design): Witness-Oriented Library Design
+  - [Episode 40](https://www.pointfree.co/episodes/ep40-async-functional-refactoring): Async Functional Refactoring
+  - [Episode 41](https://www.pointfree.co/episodes/ep41-a-tour-of-snapshot-testing): A Tour of Snapshot Testing 🆓
 
-<a href="https://www.pointfree.co/episodes/ep26-domain-specific-languages-part-1">
-  <img alt="video poster image" src="https://d1hf1soyumxcgv.cloudfront.net/0039-witness-oriented-library-design/poster.jpg" width="480">
+<a href="https://www.pointfree.co/episodes/ep41-a-tour-of-snapshot-testing">
+  <img alt="video poster image" src="https://d1hf1soyumxcgv.cloudfront.net/0041-tour-of-snapshot-testing/0041-poster.jpg" width="480">
 </a>
 
 ## License