Updated token renewal strategy to ask for a new token if the existing one expires in next 60 sec (#43)

Author: Anatoli Kurtsevich

rai-sdk/src/main/java/com/relationalai/AccessToken.java

@@ -43,8 +43,8 @@ long nowEpochSecs() {
     }
 
     // Answers if the token is expired.
-    // Anticipate access token expiration by 5 seconds
+    // Anticipate access token expiration by 60 seconds
     public boolean isExpired() {
-        return nowEpochSecs() > expiresOn() - 5;
+        return nowEpochSecs() > expiresOn() - 60;
     }
 }