Update README to match reality

Author: xrmx

README.md

@@ -80,12 +80,12 @@ This distribution sets the following defaults:
 - `OTEL_METRICS_EXPORTER`: `otlp`
 - `OTEL_LOGS_EXPORTER`: `otlp`
 - `OTEL_EXPORTER_OTLP_PROTOCOL`: `grpc`
-- `OTEL_EXPERIMENTAL_RESOURCE_DETECTORS`: `process_runtime,os,otel,telemetry_distro,aws_ec2,aws_ecs,aws_elastic_beanstalk,azure_app_service,azure_vm`
+- `OTEL_EXPERIMENTAL_RESOURCE_DETECTORS`: `process_runtime,os,otel,telemetry_distro,_gcp,aws_ec2,aws_ecs,aws_elastic_beanstalk,azure_app_service,azure_vm`
 - `OTEL_METRICS_EXEMPLAR_FILTER`: `always_off`
 - `OTEL_EXPORTER_OTLP_METRICS_TEMPORALITY_PREFERENCE`: `DELTA`
 
 > [!NOTE]
-> `OTEL_EXPERIMENTAL_RESOURCE_DETECTORS` cloud resource detectors are dynamically set. When running in a Kubernetes Pod it will be set to `process_runtime,os,otel,telemetry_distro,aws_eks`.
+> `OTEL_EXPERIMENTAL_RESOURCE_DETECTORS` cloud resource detectors are dynamically set. When running in a Kubernetes Pod it will be set to `process_runtime,os,otel,telemetry_distro,_gcp,aws_eks`.
 
 ### Distribution specific configuration variables