Increment version to 9.0.0-dev

[mjwolf]

Increment the version of main to 9.0.0-dev.

• Have you signed the contributor license agreement? y
• Have you followed the contributor guidelines? y
• For proposing substantial changes or additions to the schema, have you reviewed the RFC process? n/a
• If submitting code/script changes, have you verified all tests pass locally using make test? y
• If submitting schema/fields updates, have you generated new artifacts by running make and committed those changes? y
• Is your pull request against main? Unless there is a good reason otherwise, we prefer pull requests against main and will backport as needed.
• Have you added an entry to the CHANGELOG.next.md? n/a

[github-actions]

Documentation changes preview: https://ecs_bk_2400.docs-preview.app.elstc.co/diff

[taylor-swanson]

LGTM, I assume then we aren't going to have a 8.17.0 release?

[mjwolf]

LGTM, I assume then we aren't going to have a 8.17.0 release?

If there are more releases for 8.x, they'll be from the 8.x branch. There are already changes in main intended only for 9.0.0.