Missing 4.1 feature documentation - new GPU Metrics Input Plugin

[eschabell]

Missing new details from 4.1 release:

GPU Metrics Input Plugin - Collect metrics from AMD GPUs

Need new entry in this listing here: https://docs.fluentbit.io/manual/data-pipeline/inputs

[Xata]

Hello! I created some example documentation for the GPU metric plugin. I've opened a PR for it: #2112

[eschabell]

@Xata I'll follow up today and add the entry needed in Summary.md file to make this appear on the docs site to finalize this issue. Thanks again for the docs contribution!