fix: Update PsycopgInstrumentor.instrument_connection to use async cursor factory

[dspatoulas]

Description

Update PsycopgInstrumentor.instrument_connection to support both sync and async psycopg connections by configuring the appropriate cursor_factory.

Previously, instrument_connection always used the sync cursor factory and did not properly handle AsyncConnection instances. As a result, calls made through an async connection would fail because of the async context.

With this change:

• If connection is a psycopg.AsyncConnection, we set connection.cursor_factory to _new_cursor_async_factory(...).
• Otherwise, we set connection.cursor_factory to _new_cursor_factory(...).

This aligns instrument_connection with the behavior of the global instrument() helper and ensures both sync and async connections are correctly traced.

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

Updated the tests in the psycopg instrumentation test suite to cover both sync and async connections, added a new test for the async connection code path that was previously not tested.

Does This PR Require a Core Repo Change?

• Yes. - Link to PR:
• No.

Checklist:

See contributing.md for styleguide, changelog guidelines, and more.

• Followed the style guidelines of this project
• Changelogs have been updated
• Unit tests have been added
• Documentation has been updated

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: xrmx / name: Riccardo Magliocchetti (077bd96, 5c9da3a)

[herin049]

Can we add some unit tests to cover this scenario? Also make sure to add a changelog entry.

[dspatoulas]

Can we add some unit tests to cover this scenario? Also make sure to add a changelog entry.

Yup, updated the existing tests and added a new test for this change.

[xrmx]

Please rebase / merge main and add a CHANGELOG entry.

[dspatoulas]

Please rebase / merge main and add a CHANGELOG entry.

Rebased and updated the CHANGELOG with fix details

[xrmx]

@dspatoulas pylint is not happy

opentelemetry-instrumentation-psycopg/tests/test_psycopg_integration.py:116:4: W0221: Number of parameters was 2 in 'AsyncConnection.cursor' and is now 1 in overriding 'MockAsyncConnection.cursor' method (arguments-differ)

[dspatoulas]

@dspatoulas pylint is not happy

opentelemetry-instrumentation-psycopg/tests/test_psycopg_integration.py:116:4: W0221: Number of parameters was 2 in 'AsyncConnection.cursor' and is now 1 in overriding 'MockAsyncConnection.cursor' method (arguments-differ)

@xrmx sorry about that, I ran the tests locally but not the linter 🤦‍♂️