增加对获取自身ip对应的iso3166代码的支持

提升版本号，之前一直都没改过，之后应该都会改了

src/main/java/xyz/thewhitedog9487/WebAPI/Controller/IP.java

@@ -35,7 +35,18 @@ class IP {
                         HttpStatus.OK); }
         else {
             return new ResponseEntity<>(Request.getRemoteAddr(),
+                    MultiValueMap.fromSingleValue(Map.of("Content-Type", "text/plain;charset=UTF-8")),
+                    HttpStatus.OK); } }
+
+    @GetMapping("iso3166")
+    ResponseEntity<String> GetISO3166(@RequestHeader Map<String, String> HttpHeader) {
+        if (HttpHeader.get("CF-IPCountry".toLowerCase()) instanceof String CountryCode) {
+            return new ResponseEntity<>(CountryCode,
                     MultiValueMap.fromSingleValue(Map.of("Content-Type", "text/plain;charset=UTF-8")),
                     HttpStatus.OK); }
-    }
+        else {
+            log.warn("请求尝试获取其ip对应的iso3166代码，但是我们没有找到CF-IPCountry头部");
+            return new ResponseEntity<>("未找到CF-IPCountry头部",
+                    MultiValueMap.fromSingleValue(Map.of("Content-Type", "text/plain;charset=UTF-8")),
+                    HttpStatus.NOT_FOUND); } }
 }