[SalesForce] “Invalid literal value for picklist:” Error when deploying WorkflowFieldUpdate via ANT

If your Lead object employs Record Types, the most likely culprit for this error is that you have not included relevant Record Type(s) in your deployment.

The error bad value for restricted picklist field is encountered when a picklist option isn't available for that field under the specific Record Type of an inserted Lead record (perhaps the default Record Type, in your case).

Including the relevant Record Type in your deployment will bring over the picklist options for all picklist fields as they've been configured for that Record Type in your sandbox, and in most cases will resolve the error without having to create the field manually in Production beforehand.

Oh! I was missing the latest metadata API version which is for the picklist API name feature that was added in Spring ’17 release. I retrieved after changing package.xml to version 39 and then deployed and it worked. https://developer.salesforce.com/blogs/developer-relations/2017/01/keeping-picklist-integrations-safe-using-api-names.html