try setting up free-threading tests

.github/workflows/test.yml

@@ -49,7 +49,7 @@ jobs:
             zmq: bundled
 
           - os: macos-14
-            python: "3.13-dev"
+            python: "3.13"
             zmq: bundled
 
           - os: macos-13
@@ -86,7 +86,11 @@ jobs:
             python: "3.12"
 
           - os: ubuntu-22.04
-            python: "3.13-dev"
+            python: "3.13"
+
+          - os: ubuntu-22.04
+            python: "3.13"
+            free_threading: free_threading
 
           - os: windows-2022
             python: "3.7"
@@ -97,21 +101,29 @@ jobs:
             arch: x64
 
           - os: windows-2022
-            python: "3.13-dev"
+            python: "3.13"
             arch: x64
 
     steps:
       - uses: actions/checkout@v4
 
       - name: setup python
         uses: actions/setup-python@v5
+        if: ${{ !matrix.free_threading }}
         with:
           python-version: ${{ matrix.python }}
           architecture: ${{ matrix.arch || 'x64' }}
           # allows us to use '3.12' and get '-dev' while we wait
           allow-prereleases: true
           cache: pip
 
+      - name: setup python (free threading)
+        uses: deadsnakes/[email protected]
+        if: ${{ matrix.free_threading }}
+        with:
+          python-version: ${{ matrix.python }}
+          nogil: true
+
       - name: setup coverage
         if: startsWith(matrix.python, 'pypy') || startsWith(matrix.python, '3.12')
         run: |