update README

Author: anzhi0708

README.md

@@ -3,13 +3,17 @@
 **Use regular expressions to generate text.**
 This is the PyO3 Python binding of the Rust crate [regex_generate](https://github.com/CryptArchy/regex_generate).
 
+## Installation
+```bash
+pip install regex-generate-py
+```
+
 ## Usage
 
 ```python
 >>> from regex_generate_py import generate
->>> # Use regular expressions to generate text
+>>> 
 >>> pattern = r"(My|Your) name is an(ji|na|t)"
->>>
 >>> for i in range(10):
 ...     print(generate(pattern))
 ...