📣 Start managing the changelog with towncrier

This PR includes a workflow that validates that future PRs include
a changelog entry (unless the `skip-changelog` label is present on the
PR, or the PR is a dependabot PR).

Use 'poetry run towncrier create` to create entries for the changelog.

fastapi_cache/__init__.py

@@ -4,6 +4,7 @@ from fastapi_cache.coder import Coder, JsonCoder
 from fastapi_cache.key_builder import default_key_builder
 from fastapi_cache.types import Backend, KeyBuilder
 
+__version__ = "0.2.1"
 __all__ = [
     "Backend",
     "Coder",