Pull requests are not included when using "--data-source=milestones"

[rkeene]

In github-releases-notes v0.16.0, when using --data-source=milestones with "gren changelog --generate", only the issues closed by that milestone are included.

Sample GitHub.com repository milestone: https://github.com/nanocurrency/raiblocks/milestone/11?closed=1

Command: gren changelog --generate --username nanocurrency --repo raiblocks --tags V16.1 --changelog-filename ./CHANGELOG.md --override --milestone-match '{{tag_name}}' --ignore-tags-with="RC,^VERSION" --data-source milestones`

Actual Output:

# Changelog

## V16.1 (26/09/2018)
- [**bug**] Mutex deadlock [#1235](https://github.com/nanocurrency/raiblocks/issues/1235)
- [**bug**] Outbound Usage [#1214](https://github.com/nanocurrency/raiblocks/issues/1214)
- [**bug**] Increase stack size for Windows builds [#1212](https://github.com/nanocurrency/raiblocks/issues/1212)
- [**bug**] Rai node very slow sync since v15 [#1204](https://github.com/nanocurrency/raiblocks/issues/1204)

Expected output:
In addition to the 4 issues, all the merged in pull requests should be included

[alexcanessa]

Hello, this was by design actually, as I never thought that you could add PRs to milestones.

The filtering happens here (line: 828):

github-release-notes/lib/src/Gren.js

Lines 815 to 830 in 977b97f

	/**
	* Filter the issue based on gren options and labels
	*
	* @since 0.9.0
	* @private
	*
	* @param {Object} issue
	*
	* @return {Boolean}
	*/
	_filterIssue(issue) {
	const { dataSource } = this.options;
	return (issue.pull_request ? dataSource === 'prs' : dataSource === 'issues' | dataSource === 'milestones') && !this._lablesAreIgnored(issue.labels) &&
	!((this.options.onlyMilestones || dataSource === 'milestones') && !issue.milestone);
	}

[rinaldym]

Hi @alexcanessa any plans to release an update for this? I've tried messing with the filter but it seems to append all the tags for the specific issue to the release notes even though it does successfully pull the pull requests.

[alexcanessa]

@rinaldym I should be able to make this feature over Christmas. But you're welcome to work on it if you want :)

[dlsrb6342]

--data-source milestones-with-prs would be nice.