Drop support for py3.7.

Author: katajakasa

.github/workflows/python-package.yml

@@ -15,7 +15,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: ["3.7", "3.8", "3.9", "3.10", "3.11"]
+        python-version: ["3.8", "3.9", "3.10", "3.11"]
 
     steps:
     - uses: actions/checkout@v2

README.md

@@ -7,8 +7,8 @@ Aiohttp transport for Spyne RPC library.
 
 Requirements:
 
-* Python 3.7, 3.8, 3.9, 3.10, 3.11
-* Aiohttp >= 3.7.0
+* Python 3.8, 3.9, 3.10, 3.11
+* Aiohttp >= 3.9.0
 * Spyne >= 2.14.0
 
 Spyne alpha versions should also work.