Allow psr/cache ^1.0 || ^2.0 (#255)

All packages now allow v1 and v2.

Author: ruudk

composer.json

@@ -32,7 +32,7 @@
         "cache/adapter-common": "^1.1",
         "cache/tag-interop": "^1.0",
         "defuse/php-encryption": "^2.0",
-        "psr/cache": "^1.0"
+        "psr/cache": "^1.0 || ^2.0"
     },
     "require-dev": {
         "cache/filesystem-adapter": "^1.0",