GH Actions: version update for various predefined actions

A number of predefined actions have had major release, which warrant an update the workflow(s).

These updates don't actually contain any changed functionality, they are mostly just a change of the Node version used by the action itself (from Node 14 to Node 16).

Refs:
* https://github.com/actions/checkout/releases

Author: jrfnl

.github/workflows/cs.yml

@@ -24,7 +24,7 @@ jobs:
 
     steps:
       - name: Checkout code
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
 
       - name: Install PHP
         uses: shivammathur/setup-php@v2

.github/workflows/quicktest.yml

@@ -39,7 +39,7 @@ jobs:
 
     steps:
       - name: Checkout code
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
 
       # On stable PHPCS versions, allow for PHP deprecation notices.
       # Unit tests don't need to fail on those for stable releases where those issues won't get fixed anymore.

.github/workflows/test.yml

@@ -79,7 +79,7 @@ jobs:
 
     steps:
       - name: Checkout code
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
 
       - name: Setup ini config
         id: set_ini