chore: use latest version of shivammathur/setup-php

Author: KentarouTakeda

.github/workflows/ci.yml

@@ -27,7 +27,7 @@ jobs:
 
     steps:
       - name: Set up PHP
-        uses: shivammathur/setup-php@2.9.0
+        uses: shivammathur/setup-php@v2
         with:
           php-version: ${{ matrix.php }}
           extensions: intl, mbstring
@@ -64,7 +64,7 @@ jobs:
 
     steps:
       - name: Set up PHP
-        uses: shivammathur/setup-php@2.1.0
+        uses: shivammathur/setup-php@v2
         with:
           php-version: 7.2
 
@@ -94,7 +94,7 @@ jobs:
 
     steps:
       - name: Set up PHP
-        uses: shivammathur/setup-php@2.1.0
+        uses: shivammathur/setup-php@v2
         with:
           php-version: ${{ matrix.php }}