Update README

Author: sarahchen6

README.md

@@ -34,7 +34,7 @@ Images are built per PR for ease in testing. These test images are prefixed with
 To test these images in `dd-trace-java` CI:
 
 1. Open a PR in [DataDog/dd-trace-java-docker-build](https://github.com/DataDog/dd-trace-java-docker-build) with the changes you want to test. Let's say these changes are made in PR #123 ([example](https://github.com/DataDog/dd-trace-java-docker-build/pull/123)).
-2. Run the [Create test image mirror PR](https://github.com/DataDog/dd-trace-java-docker-build/actions/workflows/create-test-mirror-pr.yml) workflow with the corresponding PR number: `123`. This automatically opens a PR in [DataDog/images](https://github.com/DataDog/images) that adds mirror entries for the `123_merge-*` test images. Merge the PR if not done automatically by the `dd-prapprover` bot.
+2. After the PR images are built/updated in the [GitHub Container Registry](https://github.com/DataDog/dd-trace-java-docker-build/pkgs/container/dd-trace-java-docker-build), run the [Create test image mirror PR](https://github.com/DataDog/dd-trace-java-docker-build/actions/workflows/create-test-mirror-pr.yml) workflow with the corresponding PR number: `123`. This automatically opens a PR in [DataDog/images](https://github.com/DataDog/images) that adds mirror entries for the `123_merge-*` test images. Merge the PR if not done automatically by the `dd-prapprover` bot.
 3. Open a PR in [DataDog/dd-trace-java](https://github.com/DataDog/dd-trace-java) that sets `BUILDER_IMAGE_VERSION_PREFIX: "123_merge-"` in `.gitlab-ci.yml`. Here, you can check your test images with `DataDog/dd-trace-java` CI.
 4. Every time you want to test changes made in PR #123, ensure the test image SHAs in `DataDog/images` are updated by running the [Create test image mirror PR](https://github.com/DataDog/dd-trace-java-docker-build/actions/workflows/create-test-mirror-pr.yml) workflow with `123`.
 5. When the test images look good and `DataDog/dd-trace-java` CI is green, merge your `DataDog/dd-trace-java-docker-build` PR #123, close the test `DataDog/dd-trace-java` PR, and **remove the test images from the `DataDog/images` repo**.