Bump jszip from 3.4.0 to 3.7.1 in /samples/lib/spa-angular-client

Bumps [jszip](https://github.com/Stuk/jszip) from 3.4.0 to 3.7.1.
- [Release notes](https://github.com/Stuk/jszip/releases)
- [Changelog](https://github.com/Stuk/jszip/blob/master/CHANGES.md)
- [Commits](Stuk/jszip@v3.4.0...v3.7.1)

---
updated-dependencies:
- dependency-name: jszip
  dependency-type: indirect
...

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Author: dependabot[bot]