feat: 외부 API 호출에 대한 예외 처리 클래스 추가

Author: dnzp75

src/main/java/com/example/log4u/common/external/exception/ExternalApiRequestException.java

@@ -0,0 +1,13 @@
+package com.example.log4u.common.external.exception;
+
+import lombok.Getter;
+import lombok.RequiredArgsConstructor;
+
+@Getter
+@RequiredArgsConstructor
+public class ExternalApiRequestException extends RuntimeException{
+
+    private final String statusCode;
+    private final String message;
+
+}