Bump jszip, @microsoft/sp-build-web and @microsoft/sp-webpart-workbench

Bumps [jszip](https://github.com/Stuk/jszip), [@microsoft/sp-build-web](http://aka.ms/spfx) and [@microsoft/sp-webpart-workbench](http://aka.ms/spfx). These dependencies needed 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](https://github.com/Stuk/jszip/compare/v2.5.0...v3.7.1)

Updates `@microsoft/sp-build-web` from 1.4.1 to 1.15.2

Updates `@microsoft/sp-webpart-workbench` from 1.4.1 to 1.12.1

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

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

samples/react-aggregated-calendar/package.json

@@ -26,9 +26,9 @@
     "sp-client-custom-fields": "^1.3.7"
   },
   "devDependencies": {
-    "@microsoft/sp-build-web": "~1.4.1",
+    "@microsoft/sp-build-web": "~1.15.2",
     "@microsoft/sp-module-interfaces": "~1.4.1",
-    "@microsoft/sp-webpart-workbench": "~1.4.1",
+    "@microsoft/sp-webpart-workbench": "~1.12.1",
     "@types/chai": ">=3.4.34 <3.6.0",
     "@types/mocha": ">=2.2.33 <2.6.0",
     "ajv": "~5.2.2",