ci: update to actions/checkout@v4

Author: carlalexander

.github/workflows/deploy-plugin.yml

@@ -8,7 +8,7 @@ jobs:
     name: Deploy plugin to WordPress.org
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
       - name: Deploy plugin
         uses: 10up/action-wordpress-plugin-deploy@stable
         env:

.github/workflows/main.yml

@@ -7,7 +7,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout code
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
       - name: Setup PHP
         uses: shivammathur/setup-php@v2
         with:
@@ -26,7 +26,7 @@ jobs:
         php-versions: ['7.1', '7.2', '7.3', '7.4', '8.0']
     steps:
       - name: Checkout code
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
       - name: Setup PHP ${{ matrix.php-versions }}
         uses: shivammathur/setup-php@v2
         with:

.github/workflows/update-assets-readme.yml

@@ -8,7 +8,7 @@ jobs:
     name: Update plugin assets and readme on WordPress.org
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
       - name: Update plugin assets and readme
         uses: 10up/action-wordpress-plugin-asset-update@develop
         env: