code: protected void gitMergeSquash(final String branchName)
              throws MojoFailureException, CommandLineException {
          getLog().info("Squashing '" + branchName + "' branch.");
          executeGitCommand("merge", "--squash", branchName);
      }
docs: Executes git merge --squash.
  
  @param branchName
  Branch name to merge.
  @throws MojoFailureException
  @throws CommandLineException