TST: run python-dev CI on 3.14-dev

Author: ngoldbaum

.github/workflows/unit-tests.yml

@@ -313,7 +313,6 @@ jobs:
     #    To freeze this file, uncomment out the ``if: false`` condition, and migrate the jobs
     #    to the corresponding posix/windows-macos/sdist etc. workflows.
     # Feel free to modify this comment as necessary.
-    if: false
     defaults:
       run:
         shell: bash -eou pipefail {0}
@@ -345,7 +344,7 @@ jobs:
       - name: Set up Python Dev Version
         uses: actions/setup-python@v5
         with:
-          python-version: '3.13-dev'
+          python-version: '3.14-dev'
 
       - name: Build Environment
         run: |