Add free-threaded 3.14 to the CI

Author: hugovk

.github/workflows/ci.yml

@@ -9,7 +9,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python: ['3.10', '3.11', '3.12', '3.13', '3.14']
+        python: ['3.10', '3.11', '3.12', '3.13', '3.14', '3.14t']
 
     steps:
       - name: Checkout
@@ -35,7 +35,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python: ['3.10', '3.11', '3.12', '3.13', '3.14']
+        python: ['3.10', '3.11', '3.12', '3.13', '3.14', '3.14t']
         check_formatting: ['0']
         extra_name: ['']
         include:
@@ -72,7 +72,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python: ['3.10', '3.11', '3.12', '3.13', '3.14']
+        python: ['3.10', '3.11', '3.12', '3.13', '3.14', '3.14t']
     steps:
       - name: Checkout
         uses: actions/checkout@v5
@@ -83,6 +83,10 @@ jobs:
           allow-prereleases: true
           cache: pip
           cache-dependency-path: test-requirements.txt
+      - name: Set PYTHON_GIL
+        if: endsWith(matrix.python-version, 't')
+        run: |
+          echo "PYTHON_GIL=0" >> "$GITHUB_ENV"
       - name: Run tests
         run: ./ci.sh
         env: