Bump slim/psr7 from 0.6 to 1.6.1

Bumps [slim/psr7](https://github.com/slimphp/Slim-Psr7) from 0.6 to 1.6.1.
- [Release notes](https://github.com/slimphp/Slim-Psr7/releases)
- [Commits](slimphp/Slim-Psr7@0.6...1.6.1)

---
updated-dependencies:
- dependency-name: slim/psr7
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

composer.json

@@ -18,7 +18,7 @@
         "league/container": "^3.3",
         "league/route": "^4.3",
         "monolog/monolog": "^1.11",
-        "slim/psr7": "^0.6",
+        "slim/psr7": "^1.6",
         "symfony/yaml": "^4.3",
         "auth0/auth0-php": "^5.7",
         "beberlei/assert": "^3.2",