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

.github/workflows/integrationtest.yml

@@ -56,7 +56,7 @@ jobs:
 
     steps:
       - name: Checkout code
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
 
       - name: Install PHP
         uses: shivammathur/setup-php@v2

.github/workflows/linting.yaml

@@ -17,7 +17,7 @@ jobs:
   validate-composer:
     runs-on: ubuntu-18.04
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - name: Validate composer.json and composer.lock
         uses: "docker://composer"
         with:
@@ -26,7 +26,7 @@ jobs:
   lint-json:
     runs-on: ubuntu-18.04
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - name: Lint json
         uses: "docker://pipelinecomponents/jsonlint:latest"
         with:
@@ -35,20 +35,20 @@ jobs:
   yamllint:
     runs-on: ubuntu-18.04
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - name: Check yaml for issues
         uses: pipeline-components/yamllint@master
 
   php-codesniffer:
     runs-on: ubuntu-18.04
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - name: Check php for code style and php cross-version compatibility issues
         uses: pipeline-components/php-codesniffer@master
 
   lint-remark:
     runs-on: ubuntu-18.04
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - name: Check markdown
         uses: pipeline-components/remark-lint@master

.github/workflows/phplint.yml

@@ -26,7 +26,7 @@ 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
 
       - name: Install PHP
         uses: shivammathur/setup-php@v2

.github/workflows/securitycheck.yml

@@ -25,7 +25,7 @@ jobs:
 
     steps:
       - name: Checkout code
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
 
       - name: Install PHP
         uses: shivammathur/setup-php@v2