⬆️ Bump actions/checkout from 2 to 4 (#7)

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

.github/workflows/tests.yml

@@ -13,7 +13,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v4
     - name: Set up Python
       uses: actions/setup-python@v1
       with:
@@ -38,7 +38,7 @@ jobs:
             os: 'ubuntu-latest'
 
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v4
 
     - name: Set up Python ${{ matrix.python-version }}
       uses: actions/setup-python@v2
@@ -80,7 +80,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - name: Checkout source
-      uses: actions/checkout@v2
+      uses: actions/checkout@v4
     - name: Set up Python
       uses: actions/setup-python@v2
       with: