give up on python 3.7 for 3.10

Author: hobu

.github/workflows/build.yml

@@ -24,7 +24,7 @@ jobs:
       fail-fast: true
       matrix:
         os: ['ubuntu-latest', 'macos-latest', 'windows-latest']
-        python-version: ['3.7', '3.8', '3.9']
+        python-version: ['3.8', '3.9', '3.10']
 
     steps:
     - name: Check out