fix token type

Author: wistefan

it/src/test/java/org/fiware/dataspace/it/components/Wallet.java

@@ -226,7 +226,7 @@ private String requestOffer(String token, String credentialEndpoint, SupportedCo
     public String getAccessToken(String tokenEndpoint, String preAuthorizedCode) throws Exception {
         RequestBody requestBody = new FormEncodingBuilder()
                 .add("grant_type", PRE_AUTHORIZED_GRANT_TYPE)
-                .add("code", preAuthorizedCode)
+                .add("pre-authorized_code", preAuthorizedCode)
                 .build();
         Request tokenRequest = new Request.Builder()
                 .url(tokenEndpoint)