Unknown fields in `DataSink` example in README

[rouzbehsedighi]

The DataSink example in the README includes two unsupported fields:

• spec.connection.protocol
• spec.connection.insecureSkipVerify

https://github.com/SAP/metrics-operator/blob/b6e4ba181baf65c9f82a0feddd418c703ca2cf21/README.md?plain=1#L399-L400

https://github.com/SAP/metrics-operator/blob/b6e4ba181baf65c9f82a0feddd418c703ca2cf21/README.md?plain=1#L414-L415

Please review and remove them from the example to avoid confusion.