Bump jszip and @microsoft/sp-build-web

Bumps [jszip](https://github.com/Stuk/jszip) to 3.7.1 and updates ancestor dependency [@microsoft/sp-build-web](http://aka.ms/spfx). These dependencies need to be updated together.


Updates `jszip` from 2.5.0 to 3.7.1
- [Release notes](https://github.com/Stuk/jszip/releases)
- [Changelog](https://github.com/Stuk/jszip/blob/main/CHANGES.md)
- [Commits](Stuk/jszip@v2.5.0...v3.7.1)

Updates `@microsoft/sp-build-web` from 1.15.2 to 1.16.0

---
updated-dependencies:
- dependency-name: jszip
  dependency-type: indirect
- dependency-name: "@microsoft/sp-build-web"
  dependency-type: direct:development
...

Signed-off-by: dependabot[bot] <support@github.com>