Update README.md

Author: Shikha-code36

README.md

@@ -46,4 +46,4 @@ go run tutorial1/main.go
 - [x] [Constants Variables and Basic Data Types](tutorial2)
 - [x] [Functions and Control Structures](tutorial3)
 - [x] [Arrays, Slices, Maps and Loops](tutorial4)
-- [x] [Strings, Runes, and UTF-8 Encoding](tutorial4)
+- [x] [Strings, Runes, and UTF-8 Encoding](tutorial5)