Drop support for PHP 5.6 + 7.0

.github/workflows/code-style.yml

@@ -11,7 +11,7 @@ jobs:
       - name: Install php
         uses: shivammathur/setup-php@v2
         with:
-          php-version: "5.6"
+          php-version: "7.1"
 
       - name: Install dependencies
         run: composer update --dev --no-interaction --prefer-dist --no-progress --no-suggest --ansi

.github/workflows/tests.yml

@@ -6,7 +6,7 @@ jobs:
     runs-on: ubuntu-20.04
     strategy:
       matrix:
-        php: ['5.6', '7.0', '7.1', '7.2', '7.3']
+        php: ['7.1', '7.2', '7.3']
     steps:
       - name: Checkout
         uses: actions/checkout@v2

composer.json

@@ -15,7 +15,7 @@
         }
     },
     "require": {
-        "php": "^5.6 || ^7.0 || ^8.0",
+        "php": "^7.1 || ^8.0",
         "ext-zlib": "*"
     },
     "conflict": {
@@ -37,9 +37,9 @@
         "setasign/fpdf": "FPDI will extend this class but as it is also possible to use TCPDF or tFPDF as an alternative. There's no fixed dependency configured."
     },
     "require-dev": {
-        "phpunit/phpunit": "~5.7",
+        "phpunit/phpunit": "^7",
         "setasign/fpdf": "~1.8.6",
-        "tecnickcom/tcpdf": "~6.2",
+        "tecnickcom/tcpdf": "^6.2",
         "setasign/tfpdf": "~1.33",
         "squizlabs/php_codesniffer": "^3.5"
     },