Update actions/checkout action to v5

Author: renovate[bot]

.github/workflows/cd.yml

@@ -7,7 +7,7 @@ jobs:
   deploy:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v5
       - name: Set up Python
         uses: actions/setup-python@v5
         with:

.github/workflows/sphinx.yml

@@ -10,7 +10,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v4
+        uses: actions/checkout@v5
       - name: Install and Build HTML
         run: |
           pip install --upgrade pip

.github/workflows/tox_ci.yml

@@ -4,7 +4,7 @@ jobs:
   black:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v5
       - name: Run black
         uses: actions/setup-python@v5
         with:
@@ -19,7 +19,7 @@ jobs:
       matrix:
         python: ['3.9', '3.10', '3.11']
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v5
       - name: Setup Python
         uses: actions/setup-python@v5
         with: