[FEATURE] Add workflow to cleanup per-PR GitHub Actions caches on close

[mr-raj12]

Why do we need this improvement?

GitHub Actions caches accumulate per branch and per pull request. On every PR run, caches are written scoped to refs/pull/<n>/merge (via setup-node caches in the centrally managed workflows, and any additional test/build caches). When a PR is merged or closed, those caches are not removed automatically — they keep counting against the repository's 10 GB cache quota until GitHub's 7-day LRU eviction kicks in.

Under the quota, the LRU policy can evict live caches for master and for currently open PRs before it reaches the stale per-PR entries. The result is unnecessary cache misses on the branches that matter most, which increases CI time for everyone.

How will this change help?

A small maintenance workflow triggered on pull_request (type: closed) would list the caches scoped to the closing PR's ref and delete them via the GitHub REST API. Net effect:

• Cache quota freed sooner → fewer cold builds on master and on open PRs.
• No behavioral change to existing CI jobs — the new workflow runs only after a PR has closed.
• No changes to any existing workflow file, so no conflict with the # This action is centrally managed in https://github.com/asyncapi/.github/ header carried by every current workflow in this repo.

Screenshots

No response

How could it be implemented/designed?

Add a new file .github/workflows/cleanup-pr-caches.yml:

name: Cleanup caches for closed PRs

on:
  pull_request:
    types: [closed]

permissions:
  actions: write
  contents: read

jobs:
  cleanup:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/github-script@v7
        with:
          script: |
            const ref = `refs/pull/${context.payload.pull_request.number}/merge`;
            const { data } = await github.rest.actions.getActionsCacheList({
              owner: context.repo.owner,
              repo: context.repo.repo,
              ref,
            });
            for (const cache of data.actions_caches) {
              await github.rest.actions.deleteActionsCacheById({
                owner: context.repo.owner,
                repo: context.repo.repo,
                cache_id: cache.id,
              });
            }

Notes:

• New file, so it is not in scope of the central asyncapi/.github sync that overwrites existing workflows here.
• Scoped permissions (actions: write, contents: read) — no write access to repo contents.
• If the org prefers pinning actions to immutable SHAs, actions/github-script@v7 can be pinned accordingly.

🚧 Breaking changes

No

👀 Have you checked for similar open issues?

• I checked and didn't find a similar issue

🏢 Have you read the Contributing Guidelines?

• I have read the Contributing Guidelines

Are you willing to work on this issue?

Yes I am willing to submit a PR!

[github-actions]

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