fix(aioredis): handle all BaseException, not Exception in _finish_span (

#4193) (#4198)

## Description
This fixes the aioredis integration from raising `CancelledError`. As of Python 3.8 ([Docs link](https://docs.python.org/3/library/asyncio-exceptions.html#asyncio.CancelledError)), `CancelledError` now extends from `BaseException` and not `Exception`, and is currently being raised by the aioredis integration instead of being handled. The aioredis integration now catches all errors extending from `BaseException` in aioredis futures (i.e. the `_finish_span()` callback added to each future).

This should resolve #3253.

(cherry picked from commit 313a938)

Co-authored-by: Yun Kim <35776586+Yun-Kim@users.noreply.github.com>
Co-authored-by: Kyle Verhoog <kyle@verhoog.ca>

ddtrace/contrib/aioredis/patch.py

@@ -140,11 +140,12 @@ def traced_13_execute_command(func, instance, args, kwargs):
     def _finish_span(future):
         try:
             # Accessing the result will raise an exception if:
-            #   - The future was cancelled
+            #   - The future was cancelled (CancelledError)
             #   - There was an error executing the future (`future.exception()`)
             #   - The future is in an invalid state
             future.result()
-        except Exception:
+        # CancelledError exceptions extend from BaseException as of Python 3.8, instead of usual Exception
+        except BaseException:
             span.set_exc_info(*sys.exc_info())
         finally:
             span.finish()

releasenotes/notes/fix-aioredis-catch-cancellederror-223e8bb3d1aea94f.yaml

@@ -0,0 +1,4 @@
+---
+fixes:
+  - |
+    aioredis: added exception handling for `CancelledError` in the aioredis integration.