build: support Angular version 8 via ng update

[Splaktar]

Version info

Angular: 7.2.14

Firebase: 5.10.0

AngularFire: 5.1.3 and 5.2.0-beta.4

Other (e.g. Ionic/Cordova, Node, browser, operating system): macOS Mojave

How to reproduce these conditions

Failing test unit, Plunkr, or JSFiddle demonstrating the problem
Angular CLI doesn't run in those environments.

Steps to set up and reproduce

1. Create a new Angular CLI version 7 project with ng new my-app
2. add Angular Material with ng add @angular/material
3. add @angular/fire
4. try to update the project to Angular version 8 ng update --next @angular/cli @angular/core @angular/material

Sample data and security rules
N/A
<-- include/attach/link to some json sample data (or provide credentials to a sanitized, test Firebase project) -->

Debug output

** Errors in the JavaScript console ** N/A

** Output from firebase.database().enableLogging(true); ** N/A

** Screenshots ** N/A

Expected behavior

The update would succeed.

Actual behavior

The update fails with:

Package "@angular/fire" has an incompatible peer dependency to "zone.js" (requires "^0.8.0", would install "0.9.1").
Incompatible peer dependencies found. See above.

Can the version of zone.js be made a little more flexible to support Angular version 8?

https://github.com/angular/angularfire2/blob/2469e7721ffaea755ab6b95b66610e1495692342/package.json#L53

[jamesdaniels]

I added some || pipes to get rid of peers for the other deps, haven't had a chance to give it a spin against the latest. Thanks for the feedback.

Happy to accept a PR here!

Else I'll get to it with the last couple things I want to get to before 5.2 stable release.

[jamesdaniels]

^0.8.0 || ^0.9.0 would probably be the direction until we break with v6.0

[Splaktar]

Closed in f6815be.

[jamesdaniels]

Thanks again I'll include in the next beta.