ci: drop python3.8

Author: mrava87

.github/workflows/build.yml

@@ -14,7 +14,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest, macos-latest]
-        python-version: ['3.8', '3.9', '3.10', '3.11', '3.12']
+        python-version: ['3.9', '3.10', '3.11', '3.12']
         mpi: ['mpich', 'openmpi', 'intelmpi']
         rank: ['2', '3', '4']
         exclude: