The only thing that needed fixing up pertained to this section of the 1.18.x release notes:
> grpc_stats: the default value for stats_for_all_methods is switched from true to false, in order to avoid possible memory exhaustion due to an untrusted downstream sending a large number of unique method names. The previous default value was deprecated in version 1.14.0. This only changes the behavior when the value is not set. The previous behavior can be used by setting the value to true. This behavior change by be overridden by setting runtime feature envoy.deprecated_features.grpc_stats_filter_enable_stats_for_all_methods_by_default.
For now to maintain status-quo I'm explicitly setting `stats_for_all_methods=true` in all versions to avoid relying upon the default.
Additionally the naming of the emitted metrics for these gRPC requests changed slightly so the integration test assertions for `case-grpc` needed adjusting.
Note that this does NOT upgrade to xDS v3. That will come in a future PR.
Additionally:
- Ignored staticcheck warnings about how github.com/golang/protobuf is deprecated.
- Shuffled some agent/xds imports in advance of a later xDS v3 upgrade.
- Remove support for envoy 1.13.x but don't add in 1.17.x yet. We have to wait until the xDS v3 support is added in a follow-up PR.
Fixes#8425
Related changes:
- hard-fail the xDS connection attempt if the envoy version is known to be too old to be supported
- remove the RouterMatchSafeRegex proxy feature since all supported envoy versions have it
- stop using --max-obj-name-len (due to: envoyproxy/envoy#11740)
