Remove Python 3.7 CI

Author: amorison

.github/workflows/tox.yml

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