chore: update PHP version to 7.4

Author: girishpanchal30

.github/workflows/test-php.yml

@@ -13,7 +13,7 @@ jobs:
       - name: Setup PHP version
         uses: shivammathur/setup-php@v2
         with:
-          php-version: "7.2"
+          php-version: "7.4"
           extensions: simplexml
       - name: Checkout source code
         uses: actions/checkout@v2
@@ -47,7 +47,7 @@ jobs:
       - name: Setup PHP version
         uses: shivammathur/setup-php@v2
         with:
-          php-version: "7.2"
+          php-version: "7.4"
           extensions: simplexml, mysql
           tools: phpunit-polyfills
       - name: Checkout source code