Bump python_requires to >=3.8, drop importlib-metadata shim dependency

Author: akx

setup.py

@@ -34,9 +34,8 @@
     },
     author="Redis Inc.",
     author_email="[email protected]",
-    python_requires=">=3.7",
+    python_requires=">=3.8",
     install_requires=[
-        'importlib-metadata >= 1.0; python_version < "3.8"',
         'async-timeout>=4.0.2; python_full_version<="3.11.2"',
     ],
     classifiers=[
@@ -48,7 +47,6 @@
         "Programming Language :: Python",
         "Programming Language :: Python :: 3",
         "Programming Language :: Python :: 3 :: Only",
-        "Programming Language :: Python :: 3.7",
         "Programming Language :: Python :: 3.8",
         "Programming Language :: Python :: 3.9",
         "Programming Language :: Python :: 3.10",