Unable to unmarshal receiver configuration for otlp receiver

When defining a collector configuration using otlp [as specified from the collector docs](https://opentelemetry.io/docs/collector/configuration/#receivers), more specifically like this ``` receivers: otlp: protocols: grpc: endpoint: 0.0.0.0:4317 http: endpoint: 0.0.0.0:4318 ``` The otel-checker fails with ``` 1 Error(s) ✖ Collector: Could not parse file [redacted]/docker-otel-lgtm/docker/config.yaml: yaml: unmarshal errors: line 5: cannot unmarshal !!map into string line 8: cannot unmarshal !!map into string ``` Steps to reproduce - Copy the contents of docker-otel-lgtm repository: https://github.com/grafana/docker-otel-lgtm/blob/main/docker/otelcol-config.yaml to a local `config.yaml` file - `cd` into the directory containing the `config.yaml` file - Run otel checker `otel-checker --components collector --language go --collector-config-path "$(pwd)"` (--language does not matter here since we are only checking the otel collector config, use any valid value) Expected: The otel-checker succeeds at parsing the YAML configuration and outputs errors/success related to collector checks Actual: otel-checker fails when trying to parse the YAML file