proto: remove use of `Exporter` from generated protobuf files

[jrasell]

The current full linter fails when linting protobuf files due to the following errors:

github.com/hashicorp/nomad-autoscaler/plugins/apm/proto/v1/apm.pb.go:349:3: file_plugins_apm_proto_v1_apm_proto_msgTypes[0].Exporter is deprecated: Exporter will be removed the next time we bump protoimpl.GenVersion. See https://github.com/golang/protobuf/issues/1640  (SA1019)
github.com/hashicorp/nomad-autoscaler/plugins/apm/proto/v1/apm.pb.go:361:3: file_plugins_apm_proto_v1_apm_proto_msgTypes[1].Exporter is deprecated: Exporter will be removed the next time we bump protoimpl.GenVersion. See https://github.com/golang/protobuf/issues/1640  (SA1019)
github.com/hashicorp/nomad-autoscaler/plugins/apm/proto/v1/apm.pb.go:373:3: file_plugins_apm_proto_v1_apm_proto_msgTypes[2].Exporter is deprecated: Exporter will be removed the next time we bump protoimpl.GenVersion. See https://github.com/golang/protobuf/issues/1640  (SA1019)
github.com/hashicorp/nomad-autoscaler/plugins/apm/proto/v1/apm.pb.go:385:3: file_plugins_apm_proto_v1_apm_proto_msgTypes[3].Exporter is deprecated: Exporter will be removed the next time we bump protoimpl.GenVersion. See https://github.com/golang/protobuf/issues/1640  (SA1019)
github.com/hashicorp/nomad-autoscaler/plugins/base/proto/v1/base.pb.go:363:3: file_plugins_base_proto_v1_base_proto_msgTypes[0].Exporter is deprecated: Exporter will be removed the next time we bump protoimpl.GenVersion. See https://github.com/golang/protobuf/issues/1640  (SA1019)
github.com/hashicorp/nomad-autoscaler/plugins/base/proto/v1/base.pb.go:375:3: file_plugins_base_proto_v1_base_proto_msgTypes[1].Exporter is deprecated: Exporter will be removed the next time we bump protoimpl.GenVersion. See https://github.com/golang/protobuf/issues/1640  (SA1019)
github.com/hashicorp/nomad-autoscaler/plugins/base/proto/v1/base.pb.go:387:3: file_plugins_base_proto_v1_base_proto_msgTypes[2].Exporter is deprecated: Exporter will be removed the next time we bump protoimpl.GenVersion. See https://github.com/golang/protobuf/issues/1640  (SA1019)
github.com/hashicorp/nomad-autoscaler/plugins/base/proto/v1/base.pb.go:399:3: file_plugins_base_proto_v1_base_proto_msgTypes[3].Exporter is deprecated: Exporter will be removed the next time we bump protoimpl.GenVersion. See https://github.com/golang/protobuf/issues/1640  (SA1019)
github.com/hashicorp/nomad-autoscaler/plugins/shared/proto/v1/shared.pb.go:535:3: file_plugins_shared_proto_v1_shared_proto_msgTypes[0].Exporter is deprecated: Exporter will be removed the next time we bump protoimpl.GenVersion. See https://github.com/golang/protobuf/issues/1640  (SA1019)
github.com/hashicorp/nomad-autoscaler/plugins/shared/proto/v1/shared.pb.go:547:3: file_plugins_shared_proto_v1_shared_proto_msgTypes[1].Exporter is deprecated: Exporter will be removed the next time we bump protoimpl.GenVersion. See https://github.com/golang/protobuf/issues/1640  (SA1019)
github.com/hashicorp/nomad-autoscaler/plugins/shared/proto/v1/shared.pb.go:559:3: file_plugins_shared_proto_v1_shared_proto_msgTypes[2].Exporter is deprecated: Exporter will be removed the next time we bump protoimpl.GenVersion. See https://github.com/golang/protobuf/issues/1640  (SA1019)
github.com/hashicorp/nomad-autoscaler/plugins/shared/proto/v1/shared.pb.go:571:3: file_plugins_shared_proto_v1_shared_proto_msgTypes[3].Exporter is deprecated: Exporter will be removed the next time we bump protoimpl.GenVersion. See https://github.com/golang/protobuf/issues/1640  (SA1019)
github.com/hashicorp/nomad-autoscaler/plugins/shared/proto/v1/shared.pb.go:583:3: file_plugins_shared_proto_v1_shared_proto_msgTypes[4].Exporter is deprecated: Exporter will be removed the next time we bump protoimpl.GenVersion. See https://github.com/golang/protobuf/issues/1640  (SA1019)
github.com/hashicorp/nomad-autoscaler/plugins/strategy/proto/v1/strategy.pb.go:274:3: file_plugins_strategy_proto_v1_strategy_proto_msgTypes[0].Exporter is deprecated: Exporter will be removed the next time we bump protoimpl.GenVersion. See https://github.com/golang/protobuf/issues/1640  (SA1019)
github.com/hashicorp/nomad-autoscaler/plugins/strategy/proto/v1/strategy.pb.go:286:3: file_plugins_strategy_proto_v1_strategy_proto_msgTypes[1].Exporter is deprecated: Exporter will be removed the next time we bump protoimpl.GenVersion. See https://github.com/golang/protobuf/issues/1640  (SA1019)
github.com/hashicorp/nomad-autoscaler/plugins/target/proto/v1/target.pb.go:356:3: file_plugins_target_proto_v1_target_proto_msgTypes[0].Exporter is deprecated: Exporter will be removed the next time we bump protoimpl.GenVersion. See https://github.com/golang/protobuf/issues/1640  (SA1019)
github.com/hashicorp/nomad-autoscaler/plugins/target/proto/v1/target.pb.go:368:3: file_plugins_target_proto_v1_target_proto_msgTypes[1].Exporter is deprecated: Exporter will be removed the next time we bump protoimpl.GenVersion. See https://github.com/golang/protobuf/issues/1640  (SA1019)
github.com/hashicorp/nomad-autoscaler/plugins/target/proto/v1/target.pb.go:380:3: file_plugins_target_proto_v1_target_proto_msgTypes[2].Exporter is deprecated: Exporter will be removed the next time we bump protoimpl.GenVersion. See https://github.com/golang/protobuf/issues/1640  (SA1019)
github.com/hashicorp/nomad-autoscaler/plugins/target/proto/v1/target.pb.go:392:3: file_plugins_target_proto_v1_target_proto_msgTypes[3].Exporter is deprecated: Exporter will be removed the next time we bump protoimpl.GenVersion. See https://github.com/golang/protobuf/issues/1640  (SA1019)

The project should update its tooling and protobuf files, so that we remove use of the exporter. This might be as simple as updating the generation tooling, which when installing, gives the following warning:

github.com/golang/protobuf is deprecated: Use the "google.golang.org/protobuf" module instead

Until we have time to work on this, I will disable the linter check, so we can at least merge PRs.