code: public void deleteRepositoryFile(GitlabProject project, String path, String branchName, String commitMsg) throws IOException {
          Query query = new Query()
                  .append("branch", branchName)
                  .append("commit_message", commitMsg);
          String tailUrl = GitlabProject.URL + "/" + project.getId() + "/repository/files/" + sanitizePath(path) + query.toString();
          retrieve().method(DELETE).to(tailUrl, Void.class);
      }
docs: Deletes an existing file in the repository
  
  @param project    The Project
  @param path       The file path inside the repository
  @param branchName The name of a repository branch
  @param commitMsg  The commit message
  @throws IOException on gitlab api call error