Update actions/checkout action to v4

Author: renovate[bot]

.github/workflows/URL_Checker.yml

@@ -7,7 +7,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
     - name: urls-checker
       uses: urlstechie/urlchecker-action@master
       with:

.github/workflows/python-docs.yml

@@ -17,7 +17,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
       - name: Set up Python 3.8
         uses: actions/setup-python@v4
         with:

.github/workflows/python-publish.yml

@@ -23,7 +23,7 @@ jobs:
   deploy:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
     - name: Set up Python
       uses: actions/setup-python@v4
       with:

.github/workflows/python-test.yml

@@ -23,7 +23,7 @@ jobs:
   deploy:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
       - name: Set up Python
         uses: actions/setup-python@v4
         with: