Bump webmozart/assert from 1.12.1 to 2.1.6

Bumps [webmozart/assert](https://github.com/webmozarts/assert) from 1.12.1 to 2.1.6.
- [Release notes](https://github.com/webmozarts/assert/releases)
- [Changelog](https://github.com/webmozarts/assert/blob/master/CHANGELOG.md)
- [Commits](webmozarts/assert@1.12.1...2.1.6)

---
updated-dependencies:
- dependency-name: webmozart/assert
  dependency-version: 2.1.6
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

composer.json

@@ -31,7 +31,7 @@
         "phpdocumentor/reflection-docblock": "^6.0",
         "phpdocumentor/type-resolver": "^2.0",
         "symfony/polyfill-php80": "^1.28",
-        "webmozart/assert": "^1.7"
+        "webmozart/assert": "^2.1"
     },
     "require-dev": {
         "dealerdirect/phpcodesniffer-composer-installer": "^1.0",