Remove unused import

Author: Flashky

src/main/java/com/adventofcode/flashk/common/JsonUtil.java

@@ -1,7 +1,5 @@
 package com.adventofcode.flashk.common;
 
-import java.io.IOException;
-
 import com.fasterxml.jackson.core.JsonProcessingException;
 import com.fasterxml.jackson.databind.JsonNode;
 import com.fasterxml.jackson.databind.ObjectMapper;