SharePoint Online: Update folder metadata in document library

Update-CSOMFolderMetadata.ps1

function Update-CSOMFolderMetadata {
    param (
        [Parameter(Mandatory=$True)]
        $SiteURL,
        [Parameter(Mandatory=$True)]
        $FileServerRelativeUrl,
        $CreatedBy,
        $ModifiedBy,
        $CreatedOn,
        $ModifiedOn,
        [System.Management.Automation.PSCredential]
        $Credential
    )
    Add-Type -Path "C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\16\ISAPI\Microsoft.SharePoint.Client.dll"
    Add-Type -Path "C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\16\ISAPI\Microsoft.SharePoint.Client.Runtime.dll"
    $Ctx = New-Object Microsoft.SharePoint.Client.ClientContext($SiteURL)
    $Ctx.Credentials = New-Object Microsoft.SharePoint.Client.SharePointOnlineCredentials($Credential.UserName,$Credential.Password)

    #Get the Folder
    $Folder =  $Ctx.Web.GetFolderByServerRelativeUrl($FileServerRelativeUrl)
    $Ctx.Load($Folder)
    $Ctx.ExecuteQuery()

    # Get 'Created By' and 'Modified By' Users and ensure they exist in the site collection
    $Author = $Ctx.Web.EnsureUser($CreatedBy)
    $Ctx.Load($Author)
    $Editor= $Ctx.Web.EnsureUser($ModifiedBy)
    $Ctx.Load($Editor)
    $Ctx.ExecuteQuery()

    # Update Metadata of the Folder
    $ListItem = $Folder.ListItemAllFields
    if ($null -ne $CreatedBy) {$Listitem["Author"] = $Author}
    if ($null -ne $ModifiedBy) {$ListItem["Editor"] = $Editor}
    if ($null -ne $CreatedOn) {$ListItem["Created"] =  $CreatedOn}
    if ($null -ne $ModifiedOn) {$ListItem["Modified"] = $ModifiedOn}
    $ListItem.Update()
    $Ctx.ExecuteQuery()
}