feat: update readme

Author: twsc-james

ReadMe.md

@@ -2,7 +2,26 @@
 - EccSDK is a library that provides a simple way to interact with Chameleon Hash based on the ECC API.
 - You can search this package in this [nuget page](https://www.nuget.org/packages/EccSDK)
 
-## Usage
+## Usage for 1.1.*
+- add EccGenerator to generate key pair and stored into a file
+- add KeyPairDomain model to handle key pair and session key
+```csharp
+var keyPairDomain = EccGenerator.GetKeyDomain();
+
+var chameleonHashService = new ChameleonHashService(keyPairDomain);
+
+var chameleonSignature = chameleonHashService.Sign("Hello world");
+
+chameleonHashService.Verify(new ChameleonHashVerifyRequest()
+{
+    KeyPairDomain = keyPairDomain,
+    Message = "Hello world",
+    StrSignature = chameleonSignature.Value
+});
+```
+---
+
+## Usage for 1.0.*
 ```csharp
 var keyPair = EccKeyPair.GenerateKeyPair();