Added psr/container-implementation to "provide" section

Also, updated the container-interop-implementation constraint to `^1.2`.

Author: weierophinney

composer.json

@@ -45,7 +45,8 @@
         }
     },
     "provide": {
-        "container-interop/container-interop-implementation": "^1.1"
+        "container-interop/container-interop-implementation": "^1.2",
+        "psr/container-implementation": "^1.0"
     },
     "bin": [
         "bin/generate-deps-for-config-factory",