Support file upload for releases in API
Gitlab has the useful release feature, which allows to upload files to releases / tags .
Unfortunately the corresponding API functions do not include file upload .
The API functions
should have following additional parameters (compare create-new-file-in-repository):
file_name(optional) - Name of new file. Ex. release-v0.9.3.tar.gz
file_encoding(optional) - Change encoding to 'base64'. Default is text.
file_content(optional) - File content