Bump VERSION to 1.10.0

• Diff: https://gitlab.com/gitlab-org/gitlab-triage/compare/v1.9.0...bcf9254

• Release notes:

### Other changes (CI, backstage)

- !158 Improve performance of date filtering by using API query params for conditions on `created_at`/`updated_at`.
- !160 Clarify header in `#resources_for_rule`.
- !162 Make `SummaryResources` and `RuleResources` enumerable.

• Checklist before merging:

  • Diff link is up-to-date.
  • Based on the diff, lib/gitlab/triage/version.rb is updated, according to SemVer.
  • Release notes are accurate.

• Checklist after merging:

  • Update the release notes for the newly created tag.