[tests] Use classpath instead of file location for resource file after standard directory layout move

Author: hazendaz

src/test/java/org/mybatis/spring/submitted/webapp_placeholder/WebappPlaceholderTest.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2010-2022 the original author or authors.
+ * Copyright 2010-2024 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -29,7 +29,7 @@
 
 @ExtendWith(SpringExtension.class)
 @WebAppConfiguration
-@SpringJUnitConfig(locations = "file:src/test/java/org/mybatis/spring/submitted/webapp_placeholder/spring.xml")
+@SpringJUnitConfig(locations = "classpath:org/mybatis/spring/submitted/webapp_placeholder/spring.xml")
 class WebappPlaceholderTest {
 
   @Autowired