Allow psr/container ^1.1 (#604)

Author: fezfez

composer.json

@@ -16,7 +16,7 @@
         "composer/package-versions-deprecated": "^1.8",
         "phpdocumentor/reflection-docblock": "^4.3 || ^5.0",
         "phpdocumentor/type-resolver": "^1.4",
-        "psr/container": "^2",
+        "psr/container": "^1.1 || ^2",
         "psr/http-factory": "^1",
         "psr/http-message": "^1.0.1",
         "psr/http-server-handler": "^1",