Update ci.yml

Author: sgbaird

.github/workflows/ci.yml

@@ -60,7 +60,7 @@ jobs:
     strategy:
       matrix:
         python:
-        - "3.7"  # oldest Python supported by PSF
+        - "3.8"  # oldest Python supported by PSF
         - "3.11"  # newest Python that is stable
         platform:
         - ubuntu-latest