Fix: Include key in attribute sequence warning (#3639)

* Fix: Include key in attribute sequence warning

* Add CHANGELOG entry

---------

CHANGELOG.md

@@ -7,6 +7,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## Unreleased
 
+- Include key in attribute sequence warning
+  ([#3639](https://github.com/open-telemetry/opentelemetry-python/pull/3639))
 - Upgrade markupsafe, Flask and related dependencies to dev and test
   environments ([#3609](https://github.com/open-telemetry/opentelemetry-python/pull/3609))
 - Handle HTTP 2XX responses as successful in OTLP exporters

opentelemetry-api/src/opentelemetry/attributes/__init__.py

@@ -68,9 +68,10 @@ def _clean_attribute(
             # Reject attribute value if sequence contains a value with an incompatible type.
             if element_type not in _VALID_ATTR_VALUE_TYPES:
                 _logger.warning(
-                    "Invalid type %s in attribute value sequence. Expected one of "
+                    "Invalid type %s in attribute '%s' value sequence. Expected one of "
                     "%s or None",
                     element_type.__name__,
+                    key,
                     [
                         valid_type.__name__
                         for valid_type in _VALID_ATTR_VALUE_TYPES