Doesn't provide peer deps when using Yarn v2

### [REQUIRED] Describe your environment

* Operating System version: Ubuntu 18.04.2 (64-bit)
* Browser version: Firefox 78.0.1 (64-bit)
* Firebase SDK version: 7.17.1
* Firebase Product: database and auth

### [REQUIRED] Describe the problem

This doesn't support Yarn v2 because some of the `@firebase` packages don't provide their dependent's peer dependencies (e.g. `@firebase/auth` doesn't provide `@firebase/util` which is requested by `@firebase/auth-types`).

You should:
- [ ] Add the `@firebase/app-types` as a peer dependency to `@firebase/database` and `@firebase/auth`
- [ ] Add the `@firebase/util` as a peer dependency to `@firebase/auth`

#### Steps to reproduce:

1. Clone [this repository](https://github.com/tutorbookapp/tutorbook) by running:
```
$ git clone https://github.com/tutorbookapp/tutorbook
```
2. Check out to `develop` and fetch the latest changes:
```
$ git checkout develop && git pull
```
3. Make sure [you have Yarn installed](https://yarnpkg.com/getting-started/install) and then run:
```
$ yarn install
```
4. Notice that there are warnings about `@firebase/database` and `@firebase/auth` not providing their dependency's peer dependencies:
```
➤ YN0002: │ @firebase/database@npm:0.6.9 doesn't provide @firebase/app-types@0.x requested by @firebase/auth-interop-types@npm:0.1.5
➤ YN0002: │ @firebase/auth@npm:0.14.9 [387e6] doesn't provide @firebase/app-types@0.x requested by @firebase/auth-types@npm:0.10.1
➤ YN0002: │ @firebase/auth@npm:0.14.9 [387e6] doesn't provide @firebase/util@0.x requested by @firebase/auth-types@npm:0.10.1
```