Release 6.1.0

Fix DeprecationWarning: datetime.datetime.utcfromtimestamp() is depre…

…cated and scheduled for removal in a future version. (#1261)

* Fix DeprecationWarning: datetime.datetime.utcfromtimestamp() is deprecated and scheduled for removal in a future version. Use timezone-aware objects to represent datetimes in UTC: datetime.datetime.fromtimestamp(timestamp, datetime.UTC)

* Update release notes and bumped the version

* Fix CI issue realated to actions/setup-python#962

document PR #1226 fix

document PR #1226 fix

publish to pypi as a trusted publisher

Bump version to 6.0.0 (#1216)

Fix compatibility with botocore 1.33.2 (#1206)

Add 'add_version_condition' arg (#1177)

Add a flag for controlling whether `Model.save`, `Model.update` and `Model.delete` add a condition that the persisted version is the same as the in-memory one, defaulting to `True` (the "safe" behavior).

Use model's AWS credentials in threads

When a model specifies custom AWS credentials (instead of global ones), they should be used when creating new sessions in threads. Previously, threads would always use the global credentials.

Expose transaction cancellation reasons (#1156)

This will allow the caller to know e.g. which of the transaction items ran into a conflict, which can sometimes allow app logic to better handle the error without needing to make more requests.