Encrypt the XLSX file with password by using POI

ExcelXLSXEncrypt.groovy

```groovy
// http://poi.apache.org/encryption.html
import org.apache.poi.poifs.filesystem.POIFSFileSystem
import org.apache.poi.poifs.crypt.EncryptionInfo
import org.apache.poi.poifs.crypt.Encryptor
import org.apache.poi.poifs.crypt.EncryptionMode
import org.apache.poi.openxml4j.opc.OPCPackage
import org.apache.poi.openxml4j.opc.PackageAccess
import org.apache.poi.xssf.streaming.SXSSFWorkbook

    void encryptExcel(String filePath) {
        POIFSFileSystem fs = new POIFSFileSystem()

        Encryptor enc = new EncryptionInfo(EncryptionMode.agile).getEncryptor()
        enc.confirmPassword("12345678")

        OPCPackage opc = null
        OutputStream os
        try {
            opc = OPCPackage.open(filePath, PackageAccess.READ_WRITE)
            os = enc.getDataStream(fs)
            opc.save(os)
        }
        finally {
            if (opc != null){
                opc.close()
            }
            if (os != null){
                os.close()
            }
        }
        
        deleteFileIfExists(new File(filePath).toPath())
        FileOutputStream fos = null
        try {
            fos = new FileOutputStream(new File(filePath))
            fs.writeFilesystem(fos)
        }
        finally {
            if (fos != null){
                fos.close()
            }
        }
        fs.close()
    }
```

try (POIFSFileSystem fs = new POIFSFileSystem()) {
EncryptionInfo info = new EncryptionInfo(EncryptionMode.agile);
// EncryptionInfo info = new EncryptionInfo(EncryptionMode.agile, CipherAlgorithm.aes192, HashAlgorithm.sha384, -1, -1, null);
Encryptor enc = info.getEncryptor();
enc.confirmPassword("foobaa");
// Read in an existing OOXML file and write to encrypted output stream
// don't forget to close the output stream otherwise the padding bytes aren't added
try (OPCPackage opc = OPCPackage.open(new File(""), PackageAccess.READ_WRITE);
OutputStream os = enc.getDataStream(fs)) {
opc.save(os);
}
// Write out the encrypted version
try (FileOutputStream fos = new FileOutputStream("C:\.xlsx")) {
fs.writeFilesystem(fos);
}
}