Multiple schema registry URLs does not seem to be supported

[kumarp20]

Description

Using multiple schema registries results in the following error when trying to fetch the schemaID:
failed to get schema ID: Post "https://https://host1.com:8082/,https:/host2.com:8082/subjects/test-topic/versions?normalize=false\": dial tcp: lookup host1.com:8082,https: no such host"

If a single registry URL is used, it works fine.

How to reproduce

Use a comma separated list of schema registries in this example:

https://github.com/confluentinc/confluent-kafka-go/blob/master/examples/avro_specific_producer_example/avro_specific_producer_example.go

Checklist

Please provide the following information:

• confluent-kafka-go and librdkafka version (LibraryVersion()): confluent-kafka-go v2.3.0,
• Apache Kafka broker version:
• Client configuration: ConfigMap{...}
• Operating system:
• Provide client logs (with "debug": ".." as necessary)
• Provide broker log excerpts
• Critical issue