Fix phar.yml workflow

Author: ondrejmirtes

.github/workflows/phar.yml

@@ -10,6 +10,9 @@ on:
     tags:
       - '1.12.*'
 
+env:
+  COMPOSER_ROOT_VERSION: "1.12.x-dev"
+
 concurrency:
   group: phar-${{ github.ref }} # will be canceled on subsequent pushes in both branches and pull requests
   cancel-in-progress: true
@@ -76,15 +79,12 @@ jobs:
 
       - name: "Composer dump"
         run: "composer install --no-interaction --no-progress"
-        env:
-          COMPOSER_ROOT_VERSION: "1.12.x-dev"
 
       - name: "Compile PHAR for checksum"
         working-directory: "compiler/build"
         run: "php box.phar compile --no-parallel"
         env:
           PHAR_CHECKSUM: "1"
-          COMPOSER_ROOT_VERSION: "1.12.x-dev"
 
       - name: "Re-sign PHAR"
         run: "php compiler/build/resign.php tmp/phpstan.phar"