Replace breaking errors when skipping resources with logs

[vinay-gopalan]

Overview

The make generate target generates IAM resources dynamically. It uses Google's IAM Discovery API to query the resources/APIs that Google supports. Google regularly updates these with new APIs, changes and versions, and at times the responses from a particular APIs server can be flaky (See passing and failing builds for the same resources, only a few days apart).

Currently, the flaky responses from the servers (404s or 500s) break the build for the plugin (since make dev depends on the generate target). Ideally, we would simply log to the console that we are skipping a particular API because we did not receive the appropriate response from the server, instead of completely breaking CI and the build. This PR replaces the breaking error with a warning log.

Other changes:

• Updated/Added generated resources based on new API changes from Google.