GH Actions: version update for various predefined actions

A number of predefined actions have had major releases, which warrant an update to 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
* https://github.com/actions/download-artifact/releases
* https://github.com/actions/upload-artifact/releases

Author: jrfnl

.github/workflows/ci.yml

@@ -14,7 +14,7 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
 
       - name: Install PHP
         uses: shivammathur/setup-php@v2
@@ -34,7 +34,7 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
 
       - name: Install PHP
         uses: shivammathur/setup-php@v2
@@ -60,7 +60,7 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
 
       - name: Build Docker image
         uses: ./.docker/lint-xml-configuration
@@ -104,7 +104,7 @@ jobs:
         run: git config --global core.autocrlf false
 
       - name: Checkout
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
 
       - name: Install PHP with extensions
         uses: shivammathur/setup-php@v2
@@ -144,7 +144,7 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
 
       - name: Install PHP with extensions
         uses: shivammathur/setup-php@v2
@@ -186,7 +186,7 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
 
       - name: Install PHP with extensions
         uses: shivammathur/setup-php@v2
@@ -226,7 +226,7 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
 
       - name: Install PHP with extensions
         uses: shivammathur/setup-php@v2
@@ -246,7 +246,7 @@ jobs:
         run: ant phar-snapshot
 
       - name: Upload PHAR
-        uses: actions/upload-artifact@v2
+        uses: actions/upload-artifact@v3
         with:
           name: phpunit-snapshot-phar
           path: ./build/artifacts/phpunit-snapshot.phar
@@ -277,7 +277,7 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
 
       - name: Install PHP with extensions
         uses: shivammathur/setup-php@v2
@@ -294,7 +294,7 @@ jobs:
           java-version: 1.8
 
       - name: Download PHAR
-        uses: actions/download-artifact@v2
+        uses: actions/download-artifact@v3
         with:
           name: phpunit-snapshot-phar
           path: ./build/artifacts/