Webpack 5 now includes web worker support. However, the structure of the URL within the `Worker` constructor must be in a specific format.
A migration has been added for Angular v12 that will convert web workers from the old structure to the new structure.
Before: `new Worker('./app.worker', ...)`
After: `new Worker(new URL('./app.worker', import.meta.url), ...)`
With this change we add an optional migration to update Angular CLI workspace configurations to 'production' mode by default.
To run this migration use the below commands
```
ng update @angular/cli
ng update @angular/cli --migrate-only production-by-default
```
