misc: pin ddtrace to 1.15.2

[duncanista]

What does this PR do?

Pins the version of ddtrace to 1.15.2.

Motivation

Our current build process gets the latest version of ddtrace which caused new layers to pick latest changes from ddtrace where the package size was increased abruptly.

Testing Guidelines

Tested in AWS Lambda bringing a higher version of the tracer working as expected.

Additional Notes

Types of Changes

• Bug fix
• New feature
• Breaking change
• Misc (docs, refactoring, dependency upgrade, etc.)

Check all that apply

• This PR's description is comprehensive
• This PR contains breaking changes that are documented in the description
• This PR introduces new APIs or parameters that are documented and unlikely to change in the foreseeable future
• This PR impacts documentation, and it has been updated (or a ticket has been logged)
• This PR's changes are covered by the automated tests
• This PR collects user input/sensitive content into Datadog
• This PR passes the integration tests (ask a Datadog member to run the tests)

[pvicente]

Hey @astuyve, is this pin still needed?. I want to get latest versions of datadog-lambda but with newer dd-trace-py, at least up to 1.18.6 or 1.9.x? could it be possible from your side?

[astuyve]

Will respond in the issue, thanks!