Drop support for PHP < 7.4

Author: mmoll

Diff for: .travis.yml

@@ -3,8 +3,6 @@ os:
   - linux
 language: php
 php:
-  - 7.2
-  - 7.3
   - 7.4
 env:
   - DEPENDENCIES=lowest
@@ -32,19 +30,19 @@ script:
   - vendor/bin/phpstan analyse --no-progress # Run PHPStan
   - vendor/bin/psalm --show-info=false # run psalm
   - if [ "${DEPENDENCIES}" = "highest" ]; then vendor/bin/phan -i; fi; # Run phan
-  - if [ "${TRAVIS_PHP_VERSION}" != "7.3" ]; then php -d zend_extension=xdebug.so vendor/bin/phpunit --coverage-clover=coverage.xml; fi; # Generate Code coverage report
+  - if [ "${TRAVIS_PHP_VERSION}" != "7.4" ]; then php -d zend_extension=xdebug.so vendor/bin/phpunit --coverage-clover=coverage.xml; fi; # Generate Code coverage report
 
 jobs:
   include:
     - stage: Test
-      name: PHP:7.3 Windows
+      name: PHP:7.4 Windows
       os: windows
       cache:
         directories:
           - C:/Users/travis/AppData/Local/Composer
       language: sh # No PHP currently
       env:
-        - PHP_VERSION=7.3
+        - PHP_VERSION=7.4
         - DEPENDENCIES=lowest
       install:
         - export EXACT_PHP_VERSION=$(choco search php --exact --all-versions --limit-output | grep $PHP_VERSION | cut -d \| -f 2)

Diff for: MO4/Library/PregLibrary.php

@@ -34,6 +34,8 @@ class PregLibrary
      * @return string[]|array[]
      *
      * @throws RuntimeException
+     *
+     * @psalm-suppress ArgumentTypeCoercion
      */
     public static function mo4_preg_split($pattern, $subject, $limit=-1, $flags=0): array
     {

Diff for: composer.json

@@ -26,10 +26,10 @@
         "phpstan/phpstan": "^0.12.33",
         "phpstan/phpstan-strict-rules": "^0.12",
         "phpunit/phpunit": "^7.0",
-        "vimeo/psalm": "^3.8"
+        "vimeo/psalm": "^4.0"
     },
     "require": {
-        "php": "~7.2",
+        "php": "~7.4",
         "dealerdirect/phpcodesniffer-composer-installer": "~0.7",
         "escapestudios/symfony2-coding-standard": "^3.10.0",
         "slevomat/coding-standard": "^6.2.0",