ci: drop Python 3.8 and 3.9 support

Python 3.9 is 5 years old. The CI builds the Python binary for every
platform and every version from 3.8-latest, but hasn't caught a
significant issue.

Author: rustaceanrob

.github/workflows/test-python.yaml

@@ -25,8 +25,6 @@ jobs:
     strategy:
       matrix:
         python:
-          - cp38-cp38
-          - cp39-cp39
           - cp310-cp310
           - cp311-cp311
           - cp312-cp312
@@ -70,8 +68,6 @@ jobs:
     strategy:
       matrix:
         python:
-          - "3.8"
-          - "3.9"
           - "3.10"
           - "3.11"
           - "3.12"
@@ -115,8 +111,6 @@ jobs:
     strategy:
       matrix:
         python:
-          - "3.8"
-          - "3.9"
           - "3.10"
           - "3.11"
           - "3.12"
@@ -158,8 +152,6 @@ jobs:
     strategy:
       matrix:
         python:
-          - "3.8"
-          - "3.9"
           - "3.10"
           - "3.11"
           - "3.12"