Use Ubuntu 22.04 in GH workflow php-lint-test

.github/workflows/php-lint-test.yml

@@ -10,7 +10,7 @@ env:
 jobs:
   phpcs:
     name:    PHP Code Sniffer
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-22.04
     steps:
       # clone the repository
       - uses: actions/checkout@v2
@@ -32,7 +32,7 @@ jobs:
 
   lint:
     name:    PHP Linting
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-22.04
     steps:
       # clone the repository
       - uses: actions/checkout@v2
@@ -46,7 +46,7 @@ jobs:
 
   test:
     name:    PHP testing
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-22.04
     strategy:
       fail-fast:    false
       max-parallel: 10
@@ -71,7 +71,7 @@ jobs:
           bash bin/run-ci-tests.sh
   compatibility-oldest:
     name: Run unit tests on Oldest supported version
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-22.04
     env:
       WC_VERSION: 7.7.0  # the min supported version as per L-2 policy
       WP_VERSION: 'latest'
@@ -92,7 +92,7 @@ jobs:
       - run: bash bin/run-ci-tests.sh
   compatibility-beta:
     name: Run unit tests on beta WC
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-22.04
     env:
       WC_VERSION: 'beta'
       WP_VERSION: 'latest'