Support Angular 20 and CDK v20 compatibility

[yamashin4645]

Hi 👋

Thanks for maintaining this great library!

I'm currently migrating my project to Angular 20, but I noticed that ng2-date-picker has a strict peer dependency on @angular/* and @angular/cdk up to v19.

Would it be possible to update the peerDependencies to support Angular 20 and CDK v20?

"peerDependencies": {
  "@angular/common": "^16.0.0 || ^17.0.0 || ^18.0.0 || ^19.0.0 || ^20.0.0",
  "@angular/core": "^16.0.0 || ^17.0.0 || ^18.0.0 || ^19.0.0 || ^20.0.0",
  "@angular/cdk": "^19.0.0 || ^20.0.0"
}

Also, it might be helpful to check for any breaking changes in CDK Overlay or PositionStrategy that could affect popup behavior.

Thanks again!

[nstdspace]

I submittted a pr to upgrade to angular 20

[SlothSan]

@vlio20 thanks for your work on this datepicker, do you know when your likely to merge the PR providing v20 support for the package and then release it to NPM?

Cheers!

[nstdspace]

Seems like @vlio20 abandoned the project. I will just fork it for now