Description

When OTEL_SERVICE_NAME defined, but not OTEL_RESOURCE_ATTRIBUTES, error is received when detecting from env

Environment

• OS: Ubuntu 21.04
• Architecture: x86
• Go Version: 1.17
• opentelemetry-go version: v1.0.0-RC2

Steps To Reproduce

1. define env OTEL_SERVICE_NAME
2. Run program with metric
3. shows error in log: detecting resources: [partial resource: missing value: []]

Expected behavior

when OTEL_SERVICE_NAME defined, but not OTEL_RESOURCE_ATTRIBUTES, see no error.