[ci] Start testing on python 3.14-beta

Author: Pierre-Sassoulas

.github/workflows/ci.yaml

@@ -81,7 +81,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: [3.9, "3.10", "3.11", "3.12", "3.13"]
+        python-version: [3.9, "3.10", "3.11", "3.12", "3.13", "3.14-dev"]
     outputs:
       python-key: ${{ steps.generate-python-key.outputs.key }}
     steps:
@@ -139,7 +139,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: [3.9, "3.10", "3.11", "3.12", "3.13"]
+        python-version: [3.9, "3.10", "3.11", "3.12", "3.13", "3.14-dev"]
     steps:
       - name: Set temp directory
         run: echo "TEMP=$env:USERPROFILE\AppData\Local\Temp" >> $env:GITHUB_ENV