Add checksum elements into CompleteMultipartUploadOutput class

[mmadoo]

Using minio server with docker image minio/minio:RELEASE.2022-09-01T23-53-36Z when I do a mutipart upload, I receive the following response:

<CompleteMultipartUploadResult xmlns="http://s3.amazonaws.com/doc/2006-03-01/">
	<Location>https://minio.xxx/myBucket/bigFile</Location>
	<Bucket>myBucket</Bucket>
	<Key>bigFile</Key>
	<ETag>&#34;d991cefbc7c54591517a7d17b5188c68-104&#34;</ETag>
	<ChecksumCRC32></ChecksumCRC32>
	<ChecksumCRC32C></ChecksumCRC32C>
	<ChecksumSHA1></ChecksumSHA1>
	<ChecksumSHA256></ChecksumSHA256>
</CompleteMultipartUploadResult>

This cause a warn log like

 Oct 18, 2022 1:02:21 AM io.minio.S3Base lambda$completeMultipartUploadAsync$12 WARNING: S3 service returned unknown XML for CompleteMultipartUpload REST API. <?xml version="1.0" encoding="UTF-8"?><CompleteMultipartUploadResult xmlns="http://s3.amazonaws.com/doc/2006-03-01/"><Location>https://minio.xxx/myBucket/bigFile</Location><Bucket>myBucket</Bucket><Key>bigFile</Key><ETag>&#34;d991cefbc7c54591517a7d17b5188c68-104&#34;</ETag><ChecksumCRC32></ChecksumCRC32><ChecksumCRC32C></ChecksumCRC32C><ChecksumSHA1></ChecksumSHA1<ChecksumSHA256></ChecksumSHA256></CompleteMultipartUploadResult>

This pull request add the missing Checksum elements in CompleteMultipartUploadOutput object.

Fixes #1376