NGSTACK-1000 bump versions of PHP to 8.3 and Symfony to 7.3 in 'tests' GitHub workflow

Author: Ante Prkacin

.github/workflows/tests.yml

@@ -15,15 +15,10 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        php: ['8.1']
-        symfony: ['~5.4.0']
+        php: ['8.3']
+        symfony: ['~7.3.0']
         phpunit: ['phpunit.xml']
         deps: ['normal']
-        include:
-          - php: '8.1'
-            symfony: '~5.4.0'
-            phpunit: 'phpunit.xml'
-            deps: 'low'
 
     steps:
       - uses: actions/checkout@v2