Upgrade to Angular 18 and above

[Akxe]

Hi, In order not to block upgrades to newer versions of Angular, you could move your Angular dependencies to devEependencies, and thus allowing users to install any version they want :)

See https://github.com/VadimDez/ng2-pdf-viewer/blob/master/package.json for insiration.

[mnahkies]

This is actually already the case for the package itself - it specifies the angular dependencies as peerDependencies with version constraints based on what versions are officially supported https://github.com/mnahkies/ng-qrcode/blob/master/projects%2Fng-qrcode%2Fpackage.json#L17-L24

Most package managers will log a warning but not prevent you from going outside these constraints in my experience, though it's possible that some are stricter.

I'll be aiming to upgrade/test/release this weekend regardless.

[mnahkies]

Update to v18 released