HADOOP-18294. Ensure build folder exists before writing checksum file.ProtocRunner#writeChecksums (#4446)

Co-authored-by: Ashutosh Gupta <ashugpt@amazon.com>
Signed-off-by: Akira Ajisaka <aajisaka@apache.org>

hadoop-maven-plugins/src/main/java/org/apache/hadoop/maven/plugin/protoc/ProtocRunner.java

@@ -30,6 +30,7 @@ import java.io.FileInputStream;
 import java.io.FileNotFoundException;
 import java.io.FileOutputStream;
 import java.io.IOException;
+import java.nio.file.Files;
 import java.util.Arrays;
 import java.util.ArrayList;
 import java.util.HashMap;
@@ -172,6 +173,7 @@ public class ProtocRunner {
 
     public void writeChecksums() throws IOException {
       ObjectMapper mapper = new ObjectMapper();
+      Files.createDirectories(checksumFile.getParentFile().toPath());
       try (BufferedOutputStream out = new BufferedOutputStream(
           new FileOutputStream(checksumFile))) {
         mapper.writeValue(out, computedChecksums);