Add compatibility table to readme and docs

[beeman]

As of version 5 of angular-split there will be a minimal Angular compatibility requirement.

For example: angular-split 5.0 will only support Angular 9 and 10.

[MaximeKoitsalu]

@beeman Thanks for maintaining this project. Is upgrading to support Angular 12 in the pipe?

[beeman]

@MaximeKoitsalu yes! I totally aim to support this.

Are you currently running into any issues using it or is it a matter of warnings?

[MaximeKoitsalu]

Thanks for the quick reply! No issues yet, I'm just trying to be proactive and I was just looking through my package.json dependencies to see what dependencies might be show stoppers to upgrade to Angular 12.

[beeman]

Let me know if it's a show-stopper and I'll push out a fix.