Fix building pickle.phar on Windows

Author: mlocati

.github/workflows/test.yml

@@ -34,8 +34,14 @@ jobs:
         run: composer install --prefer-source --optimize-autoloader --ansi --no-interaction --no-dev
       - name: Install Box
         run: composer global require 'kherge/box=~2.7' --prefer-source
-      - name: Build pickle.phar
-        run: ~/.composer/vendor/bin/box build
+      - name: Build pickle.phar on Ubuntu
+        if: startsWith(matrix.os, 'ubuntu')
+        run: |
+          "$(composer global config bin-dir --absolute)/box" build
+      - name: Build pickle.phar on Windows
+        if: startsWith(matrix.os, 'windows')
+        run: |
+          & "$(composer global config bin-dir --absolute)/box.bat" build
       - name: Install Composer dependencies (including dev, preferring dist)
         run: composer install --optimize-autoloader --ansi --no-interaction
       - name: Run Behat