message: refactor(upgrade): ensure compatibility with noImplicitOverride
  Adds the `override` keyword to the `upgrade` sources to ensure
  compatibility with `noImplicitOverride`.
  PR Close
diff: @@ -232,7 +232,7 @@ class ParentInjectorPromise extends SyncPromise<Injector> {
  element.data!(this.injectorKey, this);
  }
  - resolve(injector: Injector): void {
  + override resolve(injector: Injector): void {
  // Store the real injector on the element.
  this.element.data!(this.injectorKey, injector);
  