How can I make the GActions CLI available within my Go (1.11) app that's hosted via App Engine Standard?
https://developers.google.com/assistant/tools/gactions-cli
The page that describe the capabilities for App Engine Standard says that it "Supports installing third-party binaries", but I can't find any documentation that shows how.
https://cloud.google.com/appengine/docs/the-appengine-environments
I have dug into this and, as I see it, with "third-party binaries" it means "third-party binary dependencies", thus, libraries. You cannot install other third-party binaries on GAE standard. You can learn how to import the dependencies using the Go package manager.
Regardless, if you truly need this tool, I believe that you may be interested in using GAE flex. It allows you to create a Custom Runtime where you could write a Dockerfile that installs GActions CLI.