update 2.8 branch workflows

Author: rthalley

.github/workflows/ci.yml

@@ -6,7 +6,6 @@ name: CI
 on:
   push:
     branches:
-      - main
       - 2.8
     paths:
       - '**.py'
@@ -32,8 +31,6 @@ jobs:
           - "3.14-dev"
           - "pypy3.10"
         exclude:
-          - os: windows-latest
-            python-version: "3.9"
           - os: windows-latest
             python-version: "3.10"
           - os: windows-latest
@@ -44,7 +41,7 @@ jobs:
     steps:
     - uses: actions/checkout@v5
     - name: Set up Python ${{ matrix.python-version }}
-      uses: actions/setup-python@v5
+      uses: actions/setup-python@v6
       with:
         python-version: ${{ matrix.python-version }}
         allow-prereleases: true