Bump @xmldom/xmldom from 0.7.5 to 0.7.8 (microsoft#560)

Bumps [@xmldom/xmldom](https://github.com/xmldom/xmldom) from 0.7.5 to 0.7.8.
- [Release notes](https://github.com/xmldom/xmldom/releases)
- [Changelog](https://github.com/xmldom/xmldom/blob/master/CHANGELOG.md)
- [Commits](xmldom/xmldom@0.7.5...0.7.8)

---
updated-dependencies:
- dependency-name: "@xmldom/xmldom"
  dependency-type: indirect
...

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Author: dependabot[bot]