Add 3.14 to the CI matrix

Author: ngoldbaum

.github/workflows/tests.yml

@@ -61,6 +61,8 @@ jobs:
           - "3.12"
           - "3.13"
           - "3.13t"
+          - "3.14"
+          - "3.14t"
           - "pypy-3.9"
         exclude:
           - os:
@@ -79,6 +81,7 @@ jobs:
         with:
           python-version: ${{ matrix.python }}
           cache: pip
+          allow-prereleases: true
 
       - name: Install dependencies
         run: python -m pip install tox