Fix invalid configuration example in PostgreSQL receiver README

[thc1006]

Description

This PR fixes the invalid configuration example in the PostgreSQL receiver README that was causing configuration validation errors.

Problem

The max_rows_per_query parameter was incorrectly placed under the events section, causing the error: 'events' has invalid keys: max_rows_per_query

Solution

Moved max_rows_per_query to the correct location at the root level of the receiver configuration, aligning with the actual implementation.

Related Issues

Fixes #42838

Note

This is a re-opened version of #43035. The previous PR was accidentally closed after misunderstanding the review feedback. The changelog file has been removed as requested since this is a documentation-only change.

cc @paulojmdias - Sorry for the confusion on the previous PR. I've removed the changelog file as requested.

[github-actions]

Welcome, contributor! Thank you for your contribution to opentelemetry-collector-contrib.

Important reminders:

• Please review our Contributing Guidelines.
• Don't forget to sign the Contributor License Agreement (CLA) if you haven't already.

A maintainer will review your pull request soon. Thank you for helping make OpenTelemetry better!

[paulojmdias]

/label skip-changelog

[thc1006]

Verification of the fix

I've double-checked that this PR correctly addresses issue #42838:

Problem:

• The example had max_rows_per_query incorrectly placed under the events section
• This caused the error: 'events' has invalid keys: max_rows_per_query

Solution:

• Moved max_rows_per_query to the correct locations based on the actual struct definitions in config.go:
  • Line 41: QuerySampleCollection has MaxRowsPerQuery → maps to query_sample_collection.max_rows_per_query
  • Line 31: TopQueryCollection has MaxRowsPerQuery → maps to top_query_collection.max_rows_per_query

The configuration now correctly shows:

query_sample_collection:
  max_rows_per_query: 100
top_query_collection:
  max_rows_per_query: 100
  top_n_query: 100

This aligns with the actual implementation and will no longer cause validation errors.

[github-actions]

Welcome, contributor! Thank you for your contribution to opentelemetry-collector-contrib.

Important reminders:

• Please review our Contributing Guidelines.
• Don't forget to sign the Contributor License Agreement (CLA) if you haven't already.

A maintainer will review your pull request soon. Thank you for helping make OpenTelemetry better!

[otelbot]

Thank you for your contribution @thc1006! 🎉 We would like to hear from you about your experience contributing to OpenTelemetry by taking a few minutes to fill out this survey.