Upgrading checkout CI action

Author: Carl Crowder

.github/workflows/build.yml

@@ -16,7 +16,7 @@ jobs:
         toxenv: [django_not_installed, flake8, pylint, readme]
 
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - name: Set up Python ${{ matrix.python-version }}
         uses: actions/setup-python@v4
         with:
@@ -42,7 +42,7 @@ jobs:
         django-version: [-main, "4.0"]
 
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - name: Set up Python ${{ matrix.python-version }}
         uses: actions/setup-python@v4
         with:
@@ -76,7 +76,7 @@ jobs:
         django-version: [3.2, 3.1, "3.0", "2.0", "2.2", "1.11"]
 
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - name: Set up Python ${{ matrix.python-version }}
         uses: actions/setup-python@v4
         with:
@@ -107,7 +107,7 @@ jobs:
         python-version: [3.7]
 
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - name: Set up Python ${{ matrix.python-version }}
         uses: actions/setup-python@v4
         with: