Document to add ecosystem test check in releasing task list (#7883)

See https://github.com/stylelint/stylelint-ecosystem-tester

Co-authored-by: Gary Gozlan <Mouvedia@users.noreply.github.com>

docs/maintainer-guide/releases.md

@@ -4,35 +4,37 @@
    - include the [template checklist](#new-release-issue-template)
    - if applicable, list any new rules so that we can discuss including them in our configs
 2. If necessary, open a pull request to mark those rules in [`docs/user-guide/rules.md`](../user-guide/rules.md).
-3. If necessary, test `main` locally in the:
-   1. [`stylelint/stylelint-config-recommended`](https://github.com/stylelint/stylelint-config-recommended)
-   2. [`stylelint/stylelint-config-standard`](https://github.com/stylelint/stylelint-config-standard)
-   3. [`stylelint/stylelint.io`](https://github.com/stylelint/stylelint.io)
-4. Release Stylelint:
+3. Check if package tests in [stylelint/stylelint-ecosystem-tester](https://github.com/stylelint/stylelint-ecosystem-tester) fail with the new version.
+4. If necessary, test the main branch locally against:
+   1. [stylelint/stylelint-config-recommended](https://github.com/stylelint/stylelint-config-recommended)
+   2. [stylelint/stylelint-config-standard](https://github.com/stylelint/stylelint-config-standard)
+   3. [stylelint/stylelint.io](https://github.com/stylelint/stylelint.io)
+5. Release Stylelint:
    1. If necessary, reorder the changelog entries in the "Prepare x.y.z" pull request so that the widest-reaching changes come first.
    2. Merge the "Prepare x.y.z" pull request.
    3. Open a terminal window in the `stylelint` repository.
    4. Run `npm run release`.
    5. Select the version from the [`np`](https://github.com/sindresorhus/np) prompt that matches the one in the changelog.
    6. Confirm the publishing of the package to [www.npmjs.com/package/stylelint](https://www.npmjs.com/package/stylelint).
-   7. Confirm the creation of the release at [github.com/stylelint/stylelint/releases](https://github.com/stylelint/stylelint/releases).
-5. If necessary, release `stylelint-config-*`:
+   7. Confirm the creation of the release at [stylelint/stylelint/releases](https://github.com/stylelint/stylelint/releases).
+6. If necessary, release `stylelint-config-*`:
    1. Change to the `stylelint-config-*` repository.
    2. Repeat steps 5 to 8 above for that repository.
-6. Update the website:
+7. Update the website:
    1. Go to the [releasing action page](https://github.com/stylelint/stylelint.io/actions/workflows/release-stylelint.yml) in the `stylelint.io` repository.
    2. Click **Run workflow**.
    3. Check and merge a pull request created by the action.
    4. Confirm the deployment of the update to [stylelint.io](https://stylelint.io).
-7. Check that [stylelint.io/demo](https://stylelint.io/demo) installs the latest Stylelint and config versions.
-8. Compose a tweet that:
+8. Check that [stylelint.io/demo](https://stylelint.io/demo) installs the latest Stylelint and config versions.
+9. Compose a tweet that:
    - announces the release
    - communicates what has changed
    - links to the appropriate heading in the changelog on [stylelint.io](https://stylelint.io)
 
 ## New release issue template
 
 ```markdown
+- [ ] stylelint-ecosystem-tester check
 - [ ] stylelint release
 - [ ] stylelint-config-recommended update/release
 - [ ] stylelint-config-standard update/release