Allow rxjs v7 in angular 12 projects

[jasonkenneth]

Even though Angular 12 shipped with rxjs v6, they made changes to support v7.

angular/angular#41897
angular/angular#42991
https://github.com/angular/angular/blob/fd1e7d4f0d73df42422caa056957aeaad2944a4a/packages/core/package.json#L19

When running npm install in an Angular 12 project with rxjs v7x, we get the following error.

npm ERR! Found: rxjs@7.4.0
npm ERR! node_modules/rxjs
npm ERR!   rxjs@"7.4.0" from the root project
npm ERR!   peer rxjs@"^6.5.3 || ^7.0.0" from @angular/common@12.2.12
npm ERR!   node_modules/@angular/common
npm ERR!     @angular/common@"12.2.12" from the root project
npm ERR!     peer @angular/common@"^12.0.0" from ng-inline-svg@13.1.0
npm ERR!     node_modules/ng-inline-svg
npm ERR!       ng-inline-svg@"13.1.0" from the root project
npm ERR!   1 more (@angular/core)
npm ERR!
npm ERR! Could not resolve dependency:
npm ERR! peer rxjs@"^6.6.0" from ng-inline-svg@13.1.0
npm ERR! node_modules/ng-inline-svg
npm ERR!   ng-inline-svg@"13.1.0" from the root project