chore(ci/mypy): fix broken types-protobuf (#3453) (#3456)

mergify[bot] · brettlangdon · web-flow · commit 7630d059e0de · 2022-03-21T11:41:19.000-04:00
(cherry picked from commit 96a7951) Co-authored-by: Brett Langdon <brett.langdon@datadoghq.com>
diff --git a/mypy.ini b/mypy.ini
@@ -9,6 +9,7 @@ warn_unused_ignores = true
 warn_unused_configs = true
 no_implicit_optional = true
 ignore_missing_imports = true
+namespace_packages = true
 
 [mypy-ddtrace.contrib.*]
 ignore_errors = true
