Update tests.yml

Author: staabm

.github/workflows/tests.yml

@@ -219,8 +219,6 @@ jobs:
     name: "Tests with old PHPUnit"
     runs-on: ${{ matrix.operating-system }}
     timeout-minutes: 60
-    env:
-      COMPOSER_NO_SECURITY_BLOCKING: 1
 
     strategy:
       fail-fast: false