wolfi: Improve auto-update image docs and PR body (#57588)

* Add buildkite link to PR, and update on rebuild

* Fine-tune docs

Author: willdollman

dev/ci/scripts/wolfi/update-base-image-hashes.sh

@@ -33,6 +33,8 @@ PR_TITLE="Auto-update Wolfi base images to latest"
 # PR_REVIEWER="sourcegraph/security"
 PR_LABELS="SSDLC,wolfi-auto-update,backport 5.2"
 PR_BODY="Automatically generated PR to update Wolfi base images to the latest hashes.
+
+Built from Buildkite run [#${BUILDKITE_BUILD_NUMBER}](https://buildkite.com/sourcegraph/sourcegraph/builds/${BUILDKITE_BUILD_NUMBER}).
 ## Test Plan
 - CI build verifies image functionality
 - [ ] Confirm PR should be backported to release branch"
@@ -48,7 +50,8 @@ echo ":git: Successfully commited changes and pushed to branch ${BRANCH_NAME}"
 
 # Check if an update PR already exists
 if gh pr list --head "${BRANCH_NAME}" --state open | grep -q "${PR_TITLE}"; then
-  echo ":github: A pull request already exists - no action required"
+  echo ":github: A pull request already exists - editing it"
+  gh pr edit "${BRANCH_NAME}" --body "${PR_BODY}"
 else
   # If not, create a new PR from the branch foobar-day
   # TODO: Once validated add '--reviewer "${PR_REVIEWER}"'

doc/dev/how-to/wolfi/add_update_images.md

@@ -14,9 +14,9 @@ These configuration files can be processed with apko, which will generate a base
 
 ### Update base images for a new release
 
-Before each release, we should update the base images to ensure we include any updated packages and vulnerability fixes.
+Before each release, we should update the base images to ensure we include any updated packages and vulnerability fixes. To update the images:
 
-- Review the [auto-update pull request](https://github.com/sourcegraph/sourcegraph/pulls?q=is:pr+head:wolfi-autoupdate/main+is:open) opened by Buildkite, and merge it
+- Review the [auto-update pull request](https://github.com/sourcegraph/sourcegraph/pulls?q=is:pr+head:wolfi-auto-update/main+is:open) opened by Buildkite, and merge it
 
 #### Automation
 
@@ -27,7 +27,7 @@ This process is automated by Buildkite, which runs a daily scheduled build to:
 - Update the base image hashes in `dev/oci_deps.bzl`.
 - Open, or update the already open pull request updating the hashes.
 
-To update the images (perhaps to pick up a just-released package version), [find a scheduled build](https://buildkite.com/sourcegraph/sourcegraph/builds?branch=main) in Buildkite named "Nightly Rebuild of Wolfi Base Images", and hit "Rebuild".
+To rerun the automation (perhaps to pick up a just-released package version), click the Buildkite run link in the [auto-update pull request](https://github.com/sourcegraph/sourcegraph/pulls?q=is:pr+head:wolfi-autoupdate/main+is:open) and hit "Rebuild". Alternatively, look for the latest "Nightly Rebuild of Wolfi Base Images" run [on Buildkite](https://buildkite.com/sourcegraph/sourcegraph/builds?branch=main).
 
 #### Manual image updates