Angular v20 Upgrade

[Christop406]

Hello @orizens , my company uses this package and is in the middle of an Angular upgrade now, so thought I'd send a PR your way to update the package to Angular v20!

Description

This PR upgrades the Angular dependencies to their v20 versions, and runs the migrations included therein:

• The addition to angular.json is to keep the same behavior as before, where running a schematic will add the type (e.g. component, module) between its name and .ts (ngx-infinite-scroll.directive.ts)

The npm run build command passed without issue on my end, as did the npm run test command:

Output of `npm run test`

➜  ngx-infinite-scroll git:(angular-20) ✗ npm run test                        

> orizens-ng@0.0.0 test
> ng test

✔ Browser application bundle generation complete.
29 05 2025 12:43:32.947:WARN [karma]: No captured browser, open http://localhost:9876/
29 05 2025 12:43:32.958:INFO [karma-server]: Karma v6.3.20 server started at http://localhost:9876/
29 05 2025 12:43:32.958:INFO [launcher]: Launching browsers Chrome with concurrency unlimited
29 05 2025 12:43:32.961:INFO [launcher]: Starting browser Chrome
29 05 2025 12:43:33.989:INFO [Chrome 136.0.0.0 (Mac OS 10.15.7)]: Connected on socket GW3RgfJwx2UFCvf_AAAB with id 32064113
WARN: 'Spec 'Scroll Regsiter should create a Observable of scroll observable with default 300 throttle' has no expectations.'
Chrome 136.0.0.0 (Mac OS 10.15.7): Executed 23 of 29 SUCCESS (0 secs / 0.003 secs)
WARN: 'Spec 'Scroll Regsiter should create a Observable of scroll observable without a sampleTime if throttle is 0' has no expectations.'
Chrome 136.0.0.0 (Mac OS 10.15.7): Executed 24 of 29 SUCCESS (0 secs / 0.004 secs)
Chrome 136.0.0.0 (Mac OS 10.15.7): Executed 29 of 29 SUCCESS (0.006 secs / 0.004 secs)
TOTAL: 29 SUCCESS

Let me know if you need more information! Happy to make changes as needed. 😄