Added retryAsync() method.

.gitignore

@@ -1,2 +1,3 @@
 /vendor/
 /.*/
+/composer.lock

.travis.yml

@@ -6,19 +6,30 @@ sudo: false
 language: php
 
 php:
-  - 5.5
-  - 5.6
   - 7.0
   - 7.1
+  - 7.2
+
+env:
+  matrix:
+    -
+    - DEPENDENCIES=--prefer-lowest
+
+matrix:
+  fast_finish: true
+
+cache:
+  directories:
+    - vendor
 
 install:
   - alias composer=composer\ -n && composer selfupdate
   - composer validate
-  - composer --prefer-source install
+  - composer update --no-progress --no-suggest $DEPENDENCIES
 
 script:
-  - bin/test --coverage-clover=build/logs/clover.xml
+  - composer test -- --coverage-clover=build/logs/clover.xml
 
 after_success:
-  - composer --prefer-source require satooshi/php-coveralls
-  - vendor/bin/coveralls -v
+  - composer require php-coveralls/php-coveralls:^2
+  - vendor/bin/php-coveralls -v

composer.json

@@ -13,10 +13,11 @@
     }
   ],
   "require": {
-    "php": "^5.5|^7"
+    "php": "^7"
   },
   "require-dev": {
-    "phpunit/phpunit": "^4"
+    "phpunit/phpunit": "^4.8",
+    "amphp/amp": "^2"
   },
   "autoload": {
     "files": [
@@ -25,5 +26,8 @@
     "psr-4": {
       "ScriptFUSION\\Retry\\": "src"
     }
+  },
+  "scripts": {
+    "test": "phpunit -c test"
   }
 }