Remove deprecated WriterFactory and MavenXpp3Writer usage

Author: anukalp2804

src/main/java/org/apache/maven/buildcache/checksum/MavenProjectInput.java

@@ -336,7 +336,7 @@ private boolean checkItemMatchesBaseline(ProjectsInputInfo baselineBuild, Digest
      */
     private String getEffectivePom(Model prototype) throws IOException {
         ByteArrayOutputStream output = new ByteArrayOutputStream();
-        new DefaultModelWriter().write(output, null, prototype);
+        new DefaultModelWriter().write(output, Collections.emptyMap(), prototype);
 
         // normalize env specifics
         final String[] searchList = {baseDirPath.toString(), "\\", "windows", "linux"};