add annotation from future

src/envers/__init__.py

@@ -1,6 +1,8 @@
 """Envers."""
 # mypy: disable-error-code="attr-defined"
 
+from __future__ import annotations
+
 from importlib import metadata as importlib_metadata
 
 

src/envers/__main__.py

@@ -1,5 +1,7 @@
 """The definition of the action for `python -m` command."""
 
+from __future__ import annotations
+
 from envers.cli import app
 
 if __name__ == "__main__":

tests/test_core.py

@@ -1,5 +1,7 @@
 """Tests for envers package."""
 
+from __future__ import annotations
+
 import copy
 import os
 import tempfile