chore: Cleanup refs to python 3.7 (#375)

Author: marksweb

README.rst

@@ -236,7 +236,7 @@ And then in your channels consumer, you can implement the handler:
 Dependencies
 ------------
 
-Redis server >= 5.0 is required for `channels-redis`. Python 3.7 or higher is required.
+Redis server >= 5.0 is required for `channels-redis`. Python 3.8 or higher is required.
 
 
 Used commands

setup.py

@@ -29,7 +29,7 @@
     zip_safe=False,
     packages=find_packages(exclude=["tests"]),
     include_package_data=True,
-    python_requires=">=3.7",
+    python_requires=">=3.8",
     install_requires=[
         "redis>=4.5.3",
         "msgpack~=1.0",