refactor: rename PluginInfo struct to Info

pkg/plugin/client.go

pkg/plugin/discovery/discovery.go

pkg/plugin/discovery/download.go

pkg/plugin/discovery/local.go

pkg/plugin/discovery/resolver/github/github.go

pkg/plugin/discovery/resolver/registry/registry.go

pkg/plugin/discovery/resolver/resolver.go

pkg/plugin/plugin.go

pkg/plugin/plugin_test.go

pkg/semrel/semrel.go