maint: update python version in GHA

Author: oesteban

Diff for: .github/workflows/deploy.yml

@@ -10,20 +10,21 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v4
       with:
         path: mkdocs
-    - name: Set up Python 3.8
-      uses: actions/setup-python@v1
+    - name: Set up Python 3.12
+      uses: actions/setup-python@v5
       with:
-        python-version: 3.8
+        python-version: '3.12'
+        cache: pip
     - name: Setup Git & Install dependencies
       run: |
         git config --global user.email "[email protected]"
         git config --global user.name "nipreps-bot"
         python -m pip install --upgrade pip
         pip install -r mkdocs/requirements.txt
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v4
       with:
         ref: master
         path: www