Bump actions/checkout from 3 to 4

.github/workflows/ci.yml

@@ -21,7 +21,7 @@ jobs:
     name: Check code formatting
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - name: Set up Python
         uses: actions/setup-python@v4
         with:
@@ -54,7 +54,7 @@ jobs:
         os: [ubuntu-latest, windows-latest, macos-latest]
         python-version: ["3.8", "3.9", "3.10", "3.11"]
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - name: Set up Python ${{ matrix.python-version }}
         uses: actions/setup-python@v4
         with:

.github/workflows/docs.yml

@@ -21,7 +21,7 @@ jobs:
     name: Docs building
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - name: Set up Python
         uses: actions/setup-python@v4
       - name: Install dependencies

.github/workflows/release.yml

@@ -13,7 +13,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       - name: Get history and tags for SCM versioning to work
         run: |
           git fetch --prune --unshallow
@@ -41,7 +41,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       - name: Get history and tags for SCM versioning to work
         run: |
           git fetch --prune --unshallow