Run PHPUnit outside of Composer

Author: Carlgo11

.github/workflows/php.yml renamed to .github/workflows/phpunit.yml

@@ -1,4 +1,4 @@
-name: PHP Composer
+name: PHPUnit
 
 on: [push]
 
@@ -8,15 +8,11 @@ jobs:
 
     steps:
     - uses: actions/checkout@v1
-      
-    - name: Validate composer.json and composer.lock
-      run: composer validate
-      working-directory: backend
 
     - name: Install dependencies
       run: composer install --prefer-dist --no-progress --no-suggest
       working-directory: backend
 
     - name: Run PHPUnit tests
-      run: composer exec phpunit --configuration phpunit.xml --teamcity
+      run: ./vendor/bin/phpunit -c phpunit.xml --teamcity
       working-directory: backend