Add Attachment

Adds one or more attachments to an issue. Attachments are posted as multipart/form-data ([RFC 1867](https://www.ietf.org/rfc/rfc1867.txt)).Note that: * The request must have a `X-Atlassian-Token: no-check` header, if not it is blocked. See [Special headers](#special-request-headers) for more information. * The name of the multipart/form-data parameter that contains the attachments must be `file`.The following examples upload a file called *myfile.txt* to the issu...