Drop support for Python 3.7

Python 3.7 has reached end of life.
See https://devguide.python.org/versions/.

gcn_kafka/core.py

@@ -1,11 +1,6 @@
 # SPDX-License-Identifier: CC0-1.0
 
-from typing import Any, Mapping, Optional, Union
-try:
-    from typing import Literal
-except ImportError:
-    # FIXME: Remove once we drop support for Python 3.7.
-    from typing_extensions import Literal
+from typing import Any, Literal, Mapping, Optional, Union
 from uuid import uuid4
 
 import certifi

gcn_kafka/env.py

@@ -1,8 +1,5 @@
 # SPDX-License-Identifier: CC0-1.0
 
-# FIXME: Remove after dropping support for Python 3.7
-from __future__ import annotations
-
 import os
 import re
 from typing import Optional

pyproject.toml

@@ -24,9 +24,8 @@ dependencies = [
     "certifi",
     "confluent-kafka >= 1.6.1, != 2.1.0, != 2.1.1",
     "requests",
-    "typing-extensions; python_version<='3.7'"
 ]
-requires-python = ">=3.7"
+requires-python = ">=3.8"
 dynamic = [ "version" ]
 
 [project.urls]