[DOP-2330] - update version and release notes

docs/changelog/next_release/71.breaking.rst

@@ -0,0 +1 @@
+Remove ``cover`` method from base ``HWM`` class, it only remains in ``FileHWM`` class

etl_entities/VERSION

@@ -1 +1 @@
-2.1.3
+2.2.0

etl_entities/hwm/file/file_hwm.py

@@ -15,6 +15,7 @@
 from __future__ import annotations
 
 import os
+from abc import abstractmethod
 from typing import Generic, Optional, TypeVar
 
 from pydantic import Field, validator
@@ -67,6 +68,10 @@ class FileHWM(
     class Config:  # noqa: WPS431
         json_encoders = {AbsolutePath: os.fspath}
 
+    @abstractmethod
+    def covers(self, value: FileHWMValueType) -> bool:
+        """Return ``True`` if input value is already covered by HWM"""
+
     def __eq__(self, other):
         """Checks equality of two FileHWM instances
 

etl_entities/hwm/key_value/key_value_int_hwm.py

@@ -69,6 +69,8 @@ class KeyValueIntHWM(KeyValueHWM[int]):
         )
     """
 
+    # employing frozendict without specifying `frozendict[Any, int]`
+    # due to the lack of support for generic dict annotations in Python 3.7.
     value: frozendict = Field(default_factory=frozendict)
 
     def serialize(self) -> dict: