Bump slim/psr7 from 0.5.0 to 1.6.1

Bumps [slim/psr7](https://github.com/slimphp/Slim-Psr7) from 0.5.0 to 1.6.1.
- [Release notes](https://github.com/slimphp/Slim-Psr7/releases)
- [Commits](slimphp/Slim-Psr7@0.5.0...1.6.1)

---
updated-dependencies:
- dependency-name: slim/psr7
  dependency-type: direct:production
...

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

Author: dependabot[bot]

composer.json

@@ -23,7 +23,7 @@
         "casbin/casbin": "^2.0",
         "monolog/monolog": "^2.0",
         "php-di/php-di": "^6.0",
-        "slim/psr7": "^0.5.0",
+        "slim/psr7": "^1.6.1",
         "slim/slim": "^4.2",
         "tuupola/slim-basic-auth": "^3.2"
     },