notation-go has excessive memory allocation on verification

notation-go is a collection of libraries for supporting Notation sign, verify, push, and pull of oci artifacts. Prior to version 1.0.0-rc.3, notation-go users will find their application using excessive memory when verifying signatures. The application will be killed, and thus availability is impacted. The problem has been patched in the release v1.0.0-rc.3. Some workarounds are available. Users can review their own trust policy file and check if the identity string contains `=#`. Meanwhile, users should only put trusted certificates in their trust stores referenced by their own trust policy files, and make sure the `authenticity` validation is set to `enforce`.