Fix IT compilation problem with recent merges (#297)

its/core-it-suite/src/test/resources/mng-7836-alternative-pom-syntax/maven-hocon-extension/src/main/java/org/apache/maven/hocon/PathSource.java

@@ -48,4 +48,9 @@ public class PathSource implements Source {
     public String getLocation() {
         return path.toString();
     }
+
+    @Override
+    public Source resolve(String s) {
+        return new PathSource(path.resolve(s));
+    }
 }