remove php7.2 from github workflow

Author: kenza-ya

.github/workflows/php.yml

@@ -14,7 +14,7 @@ jobs:
     strategy:
       matrix:
         operating-system: [ ubuntu-latest, macos-latest ]
-        php-versions: [ '7.2', '7.3', '7.4' ]
+        php-versions: [ '7.3', '7.4' ]
 
     steps:
     - name: Checkout