Update psr/http-message requirement from ^1.0 to ^1.0 || ^2.0

Updates the requirements on [psr/http-message](https://github.com/php-fig/http-message) to permit the latest version.
- [Release notes](https://github.com/php-fig/http-message/releases)
- [Changelog](https://github.com/php-fig/http-message/blob/master/CHANGELOG.md)
- [Commits](php-fig/http-message@1.0...2.0)

---
updated-dependencies:
- dependency-name: psr/http-message
  dependency-type: direct:production
...

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

composer.json

@@ -15,7 +15,7 @@
         "php": ">=7.1",
         "ext-json": "*",
         "guzzlehttp/guzzle": "^6.5 || ^7.0",
-        "psr/http-message": "^1.0"
+        "psr/http-message": "^1.0 || ^2.0"
     },
     "require-dev": {
         "phpstan/phpstan": "^0.12.14 || ^1.0.0",