Use newer checkout action

Author: dennisvdvliet

.github/workflows/psalm.yml

@@ -13,7 +13,7 @@ jobs:
     # Steps represent a sequence of tasks that will be executed as part of the job
     steps:
       # Checks-out your repository under $GITHUB_WORKSPACE, so your job can access it
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
 
       - name: Psalm – Static Analysis for PHP
         uses: docker://vimeo/psalm-github-actions:4.18.1

.github/workflows/tests.yml

@@ -18,7 +18,7 @@ jobs:
 
     steps:
       - name: Checkout the code
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
 
       - name: Setup PHP
         uses: shivammathur/setup-php@v2