deprecations are not errors

Author: dbu

.travis.yml

@@ -12,6 +12,7 @@ env:
         - TEST_COMMAND="composer test"
         - SYMFONY_PHPUNIT_VERSION="6.5"
         - SYMFONY_PHPUNIT_DIR="$HOME/symfony-bridge/.phpunit"
+        - SYMFONY_DEPRECATIONS_HELPER="weak"
 
 branches:
     except:
@@ -22,7 +23,7 @@ matrix:
     include:
           # Minimum supported Symfony version and latest PHP version
         - php: 7.3
-          env: COMPOSER_FLAGS="--prefer-stable --prefer-lowest" SYMFONY_DEPRECATIONS_HELPER="weak"
+          env: COMPOSER_FLAGS="--prefer-stable --prefer-lowest"
 
           # Test the latest stable release
         - php: 7.1