Constrain ddtrace version to be <2.20.0

We're seeing errors in circleci for ddtrace v2.20.0
https://app.circleci.com/pipelines/github/octoenergy/xocto/768/workflows/4444d76e-9a01-4683-a303-b240617d5bfd/jobs/746

We need to adapt xocto to support ddtrace v2.20.0, but we need to
first make sure that Kraken is ready to support this version.

In the meantime, just constrain the version of ddtrace within xocto.

pyproject.toml

@@ -25,7 +25,7 @@ classifiers = [
 ]
 license = {text = "MIT"}
 dependencies = [
-  "ddtrace>=1.9.0",
+  "ddtrace>=1.9.0,<2.20.0",
   "duckdb>=0.9.0",
   "django>=4.0",
   "openpyxl>=3.1.0",