There's a deprecation warning triggered by this library because it's using 1.x of the php-http/cache-plugin I think if you simply allowed either ^1.7 || ^2.0 it could use the later version that does not call the deprecated interface. This _might_ be related to #1119. Specifically, it's this PR: https://github.com/php-http/cache-plugin/commit/35625293aedba53ca49bb4bd06ac7d12239a89d9