Bump sirbrillig/phpcs-variable-analysis from 2.11.17 to 2.11.18 (#13629)

Bumps [sirbrillig/phpcs-variable-analysis](https://github.com/sirbrillig/phpcs-variable-analysis) from 2.11.17 to 2.11.18.
- [Release notes](https://github.com/sirbrillig/phpcs-variable-analysis/releases)
- [Commits](sirbrillig/phpcs-variable-analysis@v2.11.17...v2.11.18)

---
updated-dependencies:
- dependency-name: sirbrillig/phpcs-variable-analysis
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>