min requirements for PHP fixed

.travis.yml

@@ -3,9 +3,9 @@ language: php
 sudo: false
 
 php:
-  - 7.1
   - 7.2
   - 7.3
+  - 7.4
 
 matrix:
   fast_finish: true

composer.json

@@ -9,7 +9,7 @@
     ],
     "minimum-stability": "stable",
     "require": {
-        "php": ">=7.1",
+        "php": ">=7.2",
         "psr/http-message": "^1.0"
     },
     "require-dev": {
@@ -21,4 +21,4 @@
             "DesignPatterns\\": ""
         }
     }
-}
+}

composer.lock

@@ -4,7 +4,7 @@
         "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
         "This file is @generated automatically"
     ],
-    "content-hash": "d6f5bf553e8bd601c76284633fb58dcb",
+    "content-hash": "7ded2124a559b6f94b21d8bb99c89e7a",
     "packages": [
         {
             "name": "psr/http-message",
@@ -1636,7 +1636,7 @@
     "prefer-stable": false,
     "prefer-lowest": false,
     "platform": {
-        "php": ">=7.1"
+        "php": ">=7.2"
     },
     "platform-dev": []
 }