[ci] Remove python 3.7 and 3.8, add 3.12 runners (#624)

* [ci] Remove python 3.7 runners from test workflow.

* [ci] Remove python 3.8 from the test workflow and add 3.12 instead.

.github/workflows/test.yml

@@ -23,17 +23,12 @@ jobs:
         - macos-latest
         - windows-latest
         python-version:
-        - '3.7'
-        - '3.8'
         - '3.9'
         - '3.10'
         - '3.11'
-        - pypy-3.7
-        - pypy-3.8
+        - '3.12'
         - pypy-3.9
         - pypy-3.10
-        exclude:
-        - { platform: windows-latest, python-version: pypy-3.7 }
     steps:
     - uses: actions/checkout@v3
     - uses: actions/setup-python@v4