release: dispatch to charts repo

This commit adds a dispatch step to the release workflow that will trigger the
[`release_from_operator`
workflow](https://github.com/redpanda-data/helm-charts/blob/main/.github/workflows/release_from_operator.yaml)
in the helm-charts repo, effectively automating the entire release process[^1].

[^1]: Supposing this works as expected. Testing GHA's of this nature is quite difficult.

Author: chrisseto

.buildkite/pipeline.yml

@@ -80,7 +80,7 @@ steps:
     timeout_in_minutes: 180
     if: |
       // Only run if:
-      // 1. There's a tag and it's of the form 'v*' or 'operator/v*'
+      // 1. There's a tag in the form 'operator/v*'
       // 2. NIGHTLY_RELEASE envvar isn't set (paranoid check)
       // 3. This isn't a pull request (paranoid check)
       // 4. As buildkite schedule build on tag with the same branch settings as per the following (paranoid check)
@@ -90,7 +90,7 @@ steps:
       // > intended behaviour. Our docs aren’t really clear on this and we’re updating them now.
       //
       // https://forum.buildkite.community/t/branch-names-vs-tag-names/974/2
-      (build.tag =~ /^v/ || build.tag =~ /^operator\/v/) &&
+      (build.tag =~ /^operator\/v/) &&
       build.pull_request.id == null &&
       build.env("NIGHTLY_RELEASE") != "true" &&
       build.branch == build.tag

.github/workflows/release.yml

@@ -15,6 +15,8 @@ on:
 
 jobs:
   release:
+    permissions:
+      contents: write
     name: Create Release on GitHub
     runs-on: ubuntu-latest
 
@@ -103,4 +105,20 @@ jobs:
           files: |
             ./*.tgz
 
-      # todo(chrisseto) trigger an action in the charts repo that updates index.yaml
+      # Trigger a workflow in the helm-charts repo to update the gh-pages index.yaml.
+      # https://github.com/redpanda-data/helm-charts/blob/main/.github/workflows/release_from_operator.yaml
+      - uses: aws-actions/configure-aws-credentials@v4
+        with:
+          aws-region: ${{ vars.RP_AWS_CRED_REGION }}
+          role-to-assume: arn:aws:iam::${{ secrets.RP_AWS_CRED_ACCOUNT_ID }}:role/${{ vars.RP_AWS_CRED_BASE_ROLE_NAME }}${{ github.event.repository.name }}
+      - uses: aws-actions/aws-secretsmanager-get-secrets@v2
+        with:
+          secret-ids: |
+            ,sdlc/prod/github/actions_bot_token
+          parse-json-secrets: true
+      - name: Trigger Sync Releases in redpanda-data/helm-charts
+        uses: peter-evans/repository-dispatch@v2
+        with:
+          token: ${{ env.ACTIONS_BOT_TOKEN }}
+          repository: redpanda-data/helm-charts
+          event-type: sync-operator-repo-releases