Feat: Upload Files (#59)

This MR adds the ability to add files to comments, notes, replys, and MR descriptions via a picker.

The file will get uploaded to Gitlab and the filepath will be automatically added into the current popup buffer at the current line. You can then save the changes with the normal save functionality.

cmd/main.go

@@ -30,6 +30,7 @@ func main() {
 
 	m := http.NewServeMux()
 	m.Handle("/mr/description", withGitlabContext(http.HandlerFunc(DescriptionHandler), c))
+	m.Handle("/mr/attachment", withGitlabContext(http.HandlerFunc(AttachmentHandler), c))
 	m.Handle("/mr/reviewer", withGitlabContext(http.HandlerFunc(ReviewersHandler), c))
 	m.Handle("/mr/revisions", withGitlabContext(http.HandlerFunc(RevisionsHandler), c))
 	m.Handle("/mr/assignee", withGitlabContext(http.HandlerFunc(AssigneesHandler), c))