MINOR: [CI] Pin Python for pre-commit

Python 3.15 breaks cmake-format (cmakelang) with 'Cannot use capturing groups in re.Scanner'.

Author: jbonofre

.github/workflows/dev.yml

@@ -42,7 +42,7 @@ jobs:
 
       - uses: actions/setup-python@v7
         with:
-          python-version: '3.x'
+          python-version: '3.14'
       - name: pre-commit (cache)
         uses: actions/cache@55cc8345863c7cc4c66a329aec7e433d2d1c52a9 # v6.1.0
         with: