Retracted: Use the path github.com/open-policy-agent/opa (lower-case), not github.com/open-policy-agent/OPA.
Before 0.15.0 OPA was not using go modules and the correct import path was not enforced.
The Open Policy Agent (OPA) is an open source project that helps policy enable your application.
By integrating with OPA, your application's operators will be empowered to manage the size,
complexity, and scale of modern deployments.