fix(@schematics/angular): application migration should migrate ng-packagr builder package

The `use-application-builder` update migration will now attempt to migrate
the `ng-packagr` builder to use the `@angular/build` package if no other
`@angular-devkit/build-angular` usage is present.

Author: clydin

packages/schematics/angular/migrations/use-application-builder/migration.ts

@@ -215,6 +215,7 @@ function updateProjects(tree: Tree, context: SchematicContext) {
         case Builders.Application:
         case Builders.DevServer:
         case Builders.ExtractI18n:
+        case Builders.NgPackagr:
           // Ignore application, dev server, and i18n extraction for devkit usage check.
           // Both will be replaced if no other usage is found.
           continue;
@@ -239,6 +240,9 @@ function updateProjects(tree: Tree, context: SchematicContext) {
           case Builders.ExtractI18n:
             target.builder = '@angular/build:extract-i18n';
             break;
+          case Builders.NgPackagr:
+            target.builder = '@angular/build:ng-packagr';
+            break;
         }
       }