chore: Update box

Author: shyim

.github/workflows/phpunit.yml

@@ -41,7 +41,7 @@ jobs:
         file: ./clover.xml
 
     - name: Download box
-      run: wget https://github.com/humbug/box/releases/download/3.11.0/box.phar
+      run: wget https://github.com/humbug/box/releases/download/3.13.0/box.phar
 
     - name: Remove dev deps
       run: composer install --no-dev