Bump sirbrillig/phpcs-variable-analysis from 2.11.20 to 2.11.21

Bumps [sirbrillig/phpcs-variable-analysis](https://github.com/sirbrillig/phpcs-variable-analysis) from 2.11.20 to 2.11.21.
- [Release notes](https://github.com/sirbrillig/phpcs-variable-analysis/releases)
- [Commits](sirbrillig/phpcs-variable-analysis@v2.11.20...v2.11.21)

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

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

Diff for: composer.json

@@ -29,7 +29,7 @@
     "phpdocumentor/reflection": "^3.0",
     "phpstan/phpstan": "^1.0",
     "roave/security-advisories": "dev-latest",
-    "sirbrillig/phpcs-variable-analysis": "2.11.20",
+    "sirbrillig/phpcs-variable-analysis": "2.11.21",
     "wp-cli/export-command": "^2.0",
     "wp-cli/extension-command": "^2.0",
     "wp-cli/wp-cli": "^2.0",