chore: standardize/update release please config

[toddbaert]

Standardizes this repo's release-please setup. Part of open-feature/community-tooling#128.

• pin googleapis/release-please-action@45996ed…307cf7 # v5
• token: ${{ secrets.RELEASE_PLEASE_ACTION_TOKEN }}
• signoff configured in release-please-config.json (removes deprecated command/default-branch/signoff inputs); fixes DCO on release PRs
• release gate uses the always-emitted, monorepo-safe plural releases_created via fromJSON(... || false)
• add a concurrency guard to serialize release-please runs

Single signed-off commit; no changes to custom publish/build steps.

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ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Advanced

Run ID: 49d97451-4dd7-4b6a-b497-4749e06ef10c

📥 Commits

Reviewing files that changed from the base of the PR and between cd02a1d and 44b96c2.

📒 Files selected for processing (2)

• .github/workflows/release-please.yml
• release-please-config.json

Included review availability: Your plan provides up to 1 included review per hour; 0 remain after this review.

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📝 Walkthrough

Walkthrough

The release-please workflow adds per-ref concurrency, uses a pinned v5 action and a dedicated token, and removes two action inputs. The configuration adds a signoff identity.

Changes

Release-please settings

Layer / File(s)	Summary
Workflow and signoff settings .github/workflows/release-please.yml, release-please-config.json	The workflow adds per-ref concurrency with cancellation disabled, updates the action version and token, and removes the command and default-branch inputs. The configuration sets the signoff identity.

Estimated code review effort: 2 (Simple) | ~8 minutes

Merge Risk: ⚪ Minimal · up to 44b96

No concrete merge-blocking issue was found. Confirm the dedicated release token is configured before relying on the workflow.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly summarizes the main change: updating and standardizing the repository's release-please configuration.
Description check	✅ Passed	The description directly explains the release-please action update, token change, signoff configuration, release gate update, and concurrency guard.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check. Docstring coverage is scoped to functions touched by this diff. Analyzed 0 functions across 0…
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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