py-pip-audit: update to 2.7.0.

## [2.7.0]

### Added

* `pip-audit` now includes vulnerability aliases when `--format=json` is used,
  and also includes them in other output formats if specified by adding the
  flag `--aliases`

## [2.6.3]

### Fixed

* Removed a misleading warning message that resulted in user confusion
  ([#719](https://github.com/pypa/pip-audit/pull/719))

(wiz)