Update README.md

Author: junzhli

README.md

@@ -1,4 +1,5 @@
 # Typescript type validator
+![NPM Version](https://img.shields.io/npm/v/typescript-type-validator)
 
 A fully TypeScript-supported type validator that enables type checks at both transpile time and runtime using a flexible schema and input validation.
 
@@ -146,4 +147,4 @@ Validator.validate(schema, { evenNumber: 3 }); // Throws error
 - `field`, `objectField`, `arrayField`, `customField` — for schema definition
 - `Type` — enum for field types
 - `TypeFromSchema` — type inference from schema
-- `Validator` — class and static method for validation
+- `Validator` — class and static method for validation