Uses [v0.12.0](https://github.com/DataDog/libdatadog/releases/tag/sls-v0.12.0) of the Serverless Compatibility Layer binary.
What's Changed
* Pass serverless compat version to binary via environment variable by duncanpharvey in https://github.com/DataDog/datadog-serverless-compat-py/pull/5
* Bump version to 0.4.0 by duncanpharvey in https://github.com/DataDog/datadog-serverless-compat-py/pull/6
**Full Changelog**: https://github.com/DataDog/datadog-serverless-compat-py/compare/v0.3.0...v0.4.0