Replace URL with URI in FeignClientsRegistrar to avoid deprecation warning

The constructor 'URL(String)' has been deprecated since Java 20. Although this does not affect the current environment (Java 17), it will cause issues when upgrading to Java 21 or later.
This commit updates the URL validation in FeignClientsRegistrar.getUrl by replacing `new URL(url)` with `new URI(url)`, ensuring forward compatibility.
Verified with Java 17 and the FeignClientsRegistrarTests.

Author: HyeongDo-Myeong

spring-cloud-openfeign-core/src/main/java/org/springframework/cloud/openfeign/FeignClientsRegistrar.java

@@ -16,10 +16,8 @@
 
 package org.springframework.cloud.openfeign;
 
-import java.net.MalformedURLException;
 import java.net.URI;
 import java.net.URISyntaxException;
-import java.net.URL;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
@@ -122,9 +120,9 @@ static String getUrl(String url) {
 				url = url.substring(0, url.length() - 1);
 			}
 			try {
-				new URL(url);
+				new URI(url);
 			}
-			catch (MalformedURLException e) {
+			catch (URISyntaxException e) {
 				throw new IllegalArgumentException(url + " is malformed", e);
 			}
 		}

spring-cloud-openfeign-core/src/test/java/org/springframework/cloud/openfeign/FeignClientsRegistrarTests.java

@@ -89,6 +89,18 @@ private String testGetName(String name) {
 		return registrar.getName(Collections.singletonMap("name", name));
 	}
 
+	@Test
+	void goodUrl() {
+		String url = FeignClientsRegistrar.getUrl("https://good.url");
+		assertThat(url).as("url was wrong").isEqualTo("https://good.url");
+	}
+
+	@Test
+	void badUrl() {
+		assertThatExceptionOfType(IllegalArgumentException.class)
+			.isThrownBy(() -> FeignClientsRegistrar.getUrl("http://bad url"));
+	}
+
 	@Test
 	void testRemoveTrailingSlashFromUrl() {
 		String url = FeignClientsRegistrar.getUrl("http://localhost/");