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

All packages now allow v1 and v2.

Author: ruudk

composer.json

@@ -19,7 +19,7 @@
     "require": {
         "php": "^5.6 || ^7.0 || ^8.0",
         "cache/hierarchical-cache": "^1.0",
-        "psr/cache": "^1.0"
+        "psr/cache": "^1.0 || ^2.0"
     },
     "require-dev": {
         "cache/memcached-adapter": "^1.0",