ci: bump actions/checkout from v3 to v4 in local workflows

[mr-raj12]

Context

Four local workflow files still pin actions/checkout@v3, which runs on Node 16 and has been deprecated by GitHub. Other local workflows in this repo (validate-examples.yml, validate-embedded-examples.yml) already use actions/checkout@v4 (Node 20), so this is a consistency and hygiene cleanup.

Files affected

• .github/workflows/lint.yml
• .github/workflows/new-spec-release.yml
• .github/workflows/release.yml
• .github/workflows/update-spec.yaml

Proposed change

Replace uses: actions/checkout@v3 with uses: actions/checkout@v4 in each file above. No other change is needed — the action is backward compatible for the way these workflows use it (checkout only, no custom fetch-depth/token logic that differs between v3 and v4).

Scope note

Workflows carrying the header # This action is centrally managed in https://github.com/asyncapi/.github/ (automerge*, lint-pr-title, stale-issues-prs, etc.) sync from asyncapi/.github and must not be edited in this repo. Only the four files above are local and safe to modify.

Willing to submit a PR

Yes.

[github-actions]

Welcome to AsyncAPI. Thanks a lot for reporting your first issue. Please check out our contributors guide and the instructions about a basic recommended setup useful for opening a pull request.
Keep in mind there are also other channels you can use to interact with AsyncAPI community. For more details check out this issue.