Update README.md

Author: Majid460

README.md

@@ -18,7 +18,7 @@
  2.1.1. Armstrong Number Example 
  2.1.1. Armstrong Number with List Comprehension 
  2.1.1. Reverse a Number 
- #### 2.2. Strings 
+ #### [2.2. Strings](https://github.com/Majid460/python_practice_part1/blob/main/src/datatypes/strings/strings.py) 
  2.2.1. What is a String 
  2.2.2. String Indexing and Slicing 
  2.2.3. String Reverse with Slice