Use version range for wp-cli-tests dependency

Author: schlessera

composer.json

@@ -19,7 +19,7 @@
         "wp-cli/db-command": "^1.3 || ^2",
         "wp-cli/extension-command": "^1.2 || ^2",
         "wp-cli/media-command": "^1.1 || ^2",
-        "wp-cli/wp-cli-tests": "3.0.11"
+        "wp-cli/wp-cli-tests": "^3.0.11"
     },
     "config": {
         "process-timeout": 7200,