CI: test on python 3.8, too

Author: ev-br

.github/workflows/pip.yml

@@ -14,7 +14,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        python-version: ['3.11', '3.12', '3.13']
+        python-version: ['3.8', '3.11', '3.12', '3.13']
         numpy: ['"numpy<2.0"', "numpy"]
         os: [ubuntu-latest]
         pytest: [pytest]