Required fix version

Could you please fix fixVersion adding

Using ->setFieldValue('Fix versions','Default');
I get an error '{"errorMessages":[],"errors":{"fixVersions":"data was not an array"}}'

Payload
[10015] => {"fields":{"project":{"key":"VT"},"issuetype":{"id":"10005"},"summary":"Summary","description":"Description","fixVersions":"Default","components":[{"id":"10112"}]}}

Start by tracing setFieldValue('Fix versions', 'Default') through the JIRA issue payload construction. Compare the generated fixVersions field with the payload shown in the issue and verify the resulting request against JIRA's expected format. Done means creating an issue with a fix version no longer returns the “data was not an array” error.

Written by the indexing model from the issue text.