chore(deps): update actions/checkout action to v4

Signed-off-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

.github/workflows/main.yml

@@ -14,7 +14,7 @@ jobs:
 
     steps:
       - name: Checkout code
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
 
       - name: Set up Python
         uses: actions/setup-python@v2

.github/workflows/release.yaml

@@ -11,7 +11,7 @@ jobs:
 
     steps:
       - name: Check out the repo
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
 
       - name: Set up Python
         uses: actions/setup-python@v2