Removes [engine.io](https://github.com/socketio/engine.io). It's no longer used after updating ancestor dependencies [engine.io](https://github.com/socketio/engine.io), [@microsoft/sp-build-web](http://aka.ms/spfx) and [@microsoft/sp-webpart-workbench](http://aka.ms/spfx). These dependencies need to be updated together.
Removes `engine.io`
Updates `@microsoft/sp-build-web` from 1.4.1 to 1.16.1
Updates `@microsoft/sp-webpart-workbench` from 1.4.1 to 1.12.1
---
updated-dependencies:
- dependency-name: engine.io
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>