Drop support for old PHP versions and update dependencies accordingly (#107)

This only keeps support for PHP 8.1+, the lowest (security fix)
supported version as of today.

Author: mpdude

.github/workflows/php-version-compatibility.yml

@@ -13,7 +13,7 @@ jobs:
         strategy:
             fail-fast: false
             matrix:
-                php: [7.2, 7.4, 8.1]
+                php: [8.1, 8.2, 8.3]
         steps:
             -   name: Configure PHP version
                 uses: shivammathur/setup-php@v2

.github/workflows/release.yml

@@ -11,7 +11,7 @@ jobs:
             -   name: Configure PHP version
                 uses: shivammathur/setup-php@v2
                 with:
-                    php-version: 7.4
+                    php-version: 8.1
                     tools: composer:v2
             -   uses: actions/checkout@v4
             -   name: Install PHIVE

.github/workflows/tests.yml

@@ -12,7 +12,7 @@ jobs:
         strategy:
             fail-fast: false
             matrix:
-                php: [7.2, 7.4, 8.1]
+                php: [8.1, 8.2, 8.3]
         steps:
             -   name: Configure PHP version
                 uses: shivammathur/setup-php@v2

composer.json

@@ -15,7 +15,7 @@
         "bin/slimdump"
     ],
     "require": {
-        "php": "^7.2|8.0.*|8.1.*",
+        "php": ">= 8.1, <8.4",
         "ext-SimpleXML": "*",
         "ext-libxml": "*",
         "ext-pdo": "*",