Changing Symfony requirement to ^4 | ^5.

.gitignore

@@ -48,3 +48,4 @@
 */Entity/*~
 
 .idea
+.phpunit.result.cache

.travis.yml

@@ -1,23 +1,17 @@
 language: php
 
-branches:
-  # Only test the master branch and SemVer tags.
-  only:
-    - master
-    - /^[[:digit:]]+\.[[:digit:]]+\.[[:digit:]]+.*$/
-
+# @see https://pantheon.io/blog/highest-lowest-testing-multiple-symfony-versions
 matrix:
-  fast_finish: true
   include:
+    - php: 7.4
+      # Resolves to Symfony 5.
+      env: 'HIGHEST_LOWEST="update"'
+    - php: 7.3
+      # Resolves to Symfony 5.
+      env: 'HIGHEST_LOWEST="update"'
     - php: 7.2
-      env: 'SCENARIO=symfony4 HIGHEST_LOWEST="update"'
-    - php: 7.1
-      env: 'SCENARIO=symfony4'
-    - php: 7.0.11
+      # Resolves to Symfony 5.
       env: 'HIGHEST_LOWEST="update"'
-    - php: 7.0.11
-    - php: 5.6
-      env: 'SCENARIO=symfony2 HIGHEST_LOWEST="update --prefer-lowest'
 
 sudo: false
 
@@ -27,11 +21,15 @@ cache:
   - "$HOME/.composer/cache"
   - "vendor"
 
+before_install:
+  - composer selfupdate
+
 install:
-  - 'composer scenario "${SCENARIO}" "${HIGHEST_LOWEST-install}"'
+  - composer validate --no-check-all --ansi
+  - 'composer -n ${HIGHEST_LOWEST-install} --prefer-dist -o'
 
 script:
   - composer test
 
 after_success:
-  - travis_retry php vendor/bin/coveralls -v
+  - travis_retry php vendor/bin/coveralls -vvv

composer.json

@@ -3,10 +3,9 @@
     "description": "Expands internal property references in a yaml file.",
     "type": "library",
     "require": {
-        "php": ">=5.6",
         "dflydev/dot-access-data": "^1.1.0",
         "grasmash/expander": "^1.0.0",
-        "symfony/yaml": "^3|^4"
+        "symfony/yaml": "^4 | ^5"
     },
     "license": "MIT",
     "authors": [
@@ -21,9 +20,8 @@
         }
     },
     "require-dev": {
-        "phpunit/phpunit": "^5.5.4",
-        "satooshi/php-coveralls": "^1.0.2|dev-master",
-        "greg-1-anderson/composer-test-scenarios": "^1",
+        "phpunit/phpunit": "^8.2",
+        "php-coveralls/php-coveralls": "^2.1",
         "squizlabs/php_codesniffer": "^2.7"
     },
     "scripts": {
@@ -38,23 +36,15 @@
             "@lint",
             "@unit",
             "@cs"
-        ],
-        "scenario": "scenarios/install",
-        "post-update-cmd": [
-            "create-scenario symfony4 'symfony/console:^4.0'",
-            "create-scenario symfony2 'symfony/console:^3.0' --platform-php '5.6' --no-lockfile"
         ]
     },
     "config": {
         "optimize-autoloader": true,
-        "sort-packages": true,
-        "platform": {
-            "php": "7.1"
-        }
+        "sort-packages": true
     },
     "extra": {
         "branch-alias": {
-            "dev-master": "2.x-dev"
+            "dev-master": "3.x-dev"
         }
     }
 }