Updated minimum PHP version to 7.2

Author: casperbakker

composer.json

@@ -3,7 +3,7 @@
     "type": "library",
     "description": "An easy to use, non-bloated, barcode generator in PHP. Creates SVG, PNG, JPG and HTML images from the most used 1D barcode standards.",
     "keywords": [ "php", "barcode", "barcode generator", "EAN", "EAN13", "UPC", "Code39", "Code128", "Code93", "Standard 2 of 5", "MSI", "POSTNET", "KIX", "KIXCODE", "CODABAR", "PHARMA", "Code11", "SVG", "PNG", "HTML", "JPG", "JPEG" ],
-    "homepage": "http://github.com/picqer/php-barcode-generator",
+    "homepage": "https://github.com/picqer/php-barcode-generator",
     "license": "LGPL-3.0-or-later",
     "authors": [
         {
@@ -17,7 +17,7 @@
         }
     ],
     "require": {
-        "php": ">=5.4.0"
+        "php": ">=7.2.0"
     },
     "require-dev": {
         "phpunit/phpunit": "^5.3"