fix(profiling): add logging in profling.auto (DataDog#3134)

Added a log debug statement in ddtrace.profiling.auto to log if the
profiler has been enabled automatically on module import.

Author: P403n1x87

ddtrace/profiling/auto.py

@@ -1,5 +1,9 @@
 """Automatically starts a collector when imported."""
+from ddtrace.internal.logger import get_logger
 from ddtrace.profiling.bootstrap import sitecustomize  # noqa
 
 
+log = get_logger(__name__)
+log.debug("Enabling the profiler by auto import")
+
 start_profiler = sitecustomize.start_profiler