build: Drop Python 3.7

EOL Ended 2 months and 1 week ago (27 Jun 2023)

Author: tony

.github/workflows/tests.yml

@@ -10,7 +10,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: ["3.7", "3.11"]
+        python-version: ["3.8", "3.11"]
         tmux-version: ["2.6", "2.7", "2.8", "3.0a", "3.1b", "3.2a", "3.3a", "master"]
     steps:
       - uses: actions/checkout@v3