Automating adding contacts to a campaign based on a change to a specific field

Automating adding contacts to a campaign based on a change to a specific field

nb. I'm referring to the Campaign object in Zoho CRM here, not an email campaign in Zoho Campaigns.

I'm looking to build a workflow that will add contacts to a particular campaign when a specific field on the contact record is updated to contain specific text. As far as I can see "add to campaign" is not an option in a contact workflow. Is there a way to achieve this?