add jwt sign up or in to readme (#188)

* add jwt sign up or in to readme

* Update README.md

* Update README.md

* Update README.md

* Update README.md

---------

Co-authored-by: Tom Kaminski <tom@descope.com>

Author: ruvenzx

README.md

@@ -1190,7 +1190,41 @@ try {
 } catch (DescopeException de) {
     // Handle the error
 }
+```
+Generate a JWT for a user, simulating a signin request.
+
+```java
+JwtService jwtService = descopeClient.getManagementServices().getJwtService();
+LoginOptions loginOptions = new LoginOptions();
+loginOptions.setCustomClaims(new HashMap<String, Object>() {{
+	put("custom-key1", "custom-value1");
+	put("custom-key2", "custom-value2");
+}});
+AuthenticationInfo res = jwtService.signIn("dummy", loginOptions);
+```
+
+Generate a JWT for a user, simulating a signup request.
 
+```java
+JwtService jwtService = descopeClient.getManagementServices().getJwtService();
+MgmtSignUpUser mgmtSignUpUser = new MgmtSignUpUser();
+mgmtSignUpUser.setCustomClaims(new HashMap<String, Object>() {{
+	put("custom-key1", "custom-value1");
+	put("custom-key2", "custom-value2");
+		}});
+AuthenticationInfo res = jwtService.signUp("Dummy", mgmtSignUpUser);
+```
+
+Generate a JWT for a user, simulates a signup or in request.
+
+```java
+JwtService jwtService = descopeClient.getManagementServices().getJwtService();
+MgmtSignUpUser mgmtSignUpUser = new MgmtSignUpUser();
+mgmtSignUpUser.setCustomClaims(new HashMap<String, Object>() {{
+	put("custom-key1", "custom-value1");
+	put("custom-key2", "custom-value2");
+		}});
+AuthenticationInfo res = jwtService.signUpOrIn("Dummy", mgmtSignUpUser);
 ```
 
 ### Audit