fix(@schematics/update): update @angular/pwa when migrating to 8

Related to #14589 (comment)

Author: alan-agius4

packages/schematics/angular/migrations/update-8/update-dependencies.ts

@@ -12,6 +12,7 @@ import { latestVersions } from '../../utility/latest-versions';
 export function updateDependencies() {
   return (host: Tree) => {
     const dependenciesToUpdate: Record<string, string> = {
+      '@angular/pwa': latestVersions.AngularPWA,
       '@angular-devkit/build-angular': latestVersions.DevkitBuildAngular,
       '@angular-devkit/build-ng-packagr': latestVersions.DevkitBuildNgPackagr,
       '@angular-devkit/build-webpack': latestVersions.DevkitBuildWebpack,

packages/schematics/angular/utility/latest-versions.ts

@@ -13,10 +13,12 @@ export const latestVersions = {
   ZoneJs: '~0.9.1',
   TypeScript: '~3.4.3',
   TsLib: '^1.9.0',
+
   // The versions below must be manually updated when making a new devkit release.
   DevkitBuildAngular: '~0.801.0',
   DevkitBuildNgPackagr: '~0.801.0',
   DevkitBuildWebpack: '~0.801.0',
+  AngularPWA: '~0.801.0',
 
   tsickle: '^0.35.0',
   ngPackagr: '^5.1.0',