TEST: Add CI job for free threaded python 3.13

Author: derb12

.github/workflows/python-test.yml

@@ -31,13 +31,15 @@ jobs:
       fail-fast: false
       matrix:
         # Use strings since yaml considers 3.10 equal to 3.1
-        python-version: ['3.8', '3.9', '3.10', '3.11', '3.12', '3.13']
+        python-version: ['3.8', '3.9', '3.10', '3.11', '3.12', '3.13', '3.13t']
 
     steps:
     - uses: actions/checkout@v4
 
-    - name: Set up Python ${{ matrix.python-version }}
-      uses: actions/setup-python@v5
+    - name: Set up Python
+      # Switch back to actions/setup-python@v5 once they support free-threaded python;
+      # see revelant PR: https://github.com/actions/setup-python/pull/973
+      uses: Quansight-Labs/setup-python@v5
       with:
         python-version: ${{ matrix.python-version }}
 
@@ -52,7 +54,7 @@ jobs:
     - name: Install optional dependencies
       id: install-optional
       # uncomment below to allow skipping future versions
-      if: matrix.python-version != '3.13'
+      if: matrix.python-version != '3.13t'
       run: python -m pip install "pentapy>=1.1" "numba>=0.49"
 
     - name: Test with optional dependencies