Add an attachment to a selected issue.
path to file
Absolute path to the file.
Key of the issue the file will be attached to.
The return value represents the success of the attachment process. If the routine returns "true" the file was attached successfully.
Result: Returns "true" if the file is at the selected location and the issue exists. It means the file was attached. Returns "false" if any of the conditions stated before are not met.