Drop symfony 2.x support and require PHP >= 7.1

.travis.yml

@@ -17,10 +17,8 @@ branches:
         - master
 
 php:
-    - 5.5
-    - 5.6
-    - 7.0
     - 7.1
+    - 7.2
 
 matrix:
     fast_finish: true
@@ -36,10 +34,9 @@ before_install:
     - mkdir -p ./solr-5.3.1/example/multicore/rulerz_tests/conf && cp -r ./scripts/solr/config/conf/* ./solr-5.3.1/example/multicore/rulerz_tests/conf
 
 install:
-    - if [ "$TRAVIS_PHP_VERSION" = "7.0" ]; then composer require --dev --no-update kphoen/rusty dev-master; fi
     - composer install --optimize-autoloader --no-interaction
 
 script:
     - make databases
     - make tests
-    - if [ "$TRAVIS_PHP_VERSION" = "7.0" ]; then make rusty; fi
+    - make rusty

composer.json

@@ -32,9 +32,9 @@
         "bin-dir": "bin/"
     },
     "require": {
-        "php": ">=5.5",
+        "php": ">=7.1",
         "hoa/ruler": "~2.0",
-        "symfony/property-access": "~2.3|~3.0|~4.0"
+        "symfony/property-access": "~3.0|~4.0"
     },
     "require-dev": {
         "vlucas/phpdotenv": "~2.1",
@@ -54,6 +54,8 @@
 
         "behat/behat": "~3.0",
 
+        "kphoen/rusty": "dev-master",
+
         "liip/rmt": "^1.2"
     },
     "suggest": {