in src/functions.ts [58:67]
export async function updateMarkdown(
markdown: Buffer,
updateParams: Partial<ZennMetadata>
): Promise<Buffer> {
const updater = new Updater();
await updater.load(markdown);
const updatedZennMetadata = await updateZennMetadata(updater, updateParams);
await updater.updateProperty(updatedZennMetadata);
return updater.getUpdatedContent() as Buffer;
}