Port library to allow PHP 8.0 (#11)

* Test.yml: enable PHP 8.0

* Update composer.json

* use PHPUnit 9.5; ported tests

* updated .gitignore; removed outdated CHANGELOG.md

* allow PHPUnit 7 and 8 on lower PHP versions again

* upgraded to PHP-CS-Fixer 3.0

* updated Coding Style Action file

* try to fix a weird phpstan error

it only shows up online, offline is working.

Ref:

https://github.com/sweetrdf/easyrdf/pull/11/checks?check_run_id=3394223390#step:7:24

* add polyfill for assertMatchesRegularExpression to allow lower PHP versions

* attempt to fix failing scrutinizer tests (running out of memory)

https://scrutinizer-ci.com/g/sweetrdf/easyrdf/inspections/302a615e-6d4b-4663-8de3-17a0e79d06c6

* removed scrutinizer integration ...

... it makes no sense that random tests fail
just because it doesn't provide enough memory to run them.

it hinders development therefore removed.

* README.md: removed scrutinizer badges

.github/workflows/CodingStyles.yml

@@ -32,7 +32,7 @@ jobs:
                 run: composer install --no-progress --no-suggest --prefer-dist --optimize-autoloader
 
             -   name: Coding styles
-                run: php vendor/bin/php-cs-fixer fix --verbose --dry-run --config .php_cs --format=checkstyle | cs2pr
+                run: php vendor/bin/php-cs-fixer fix --verbose --dry-run --format=checkstyle | cs2pr
 
             -   name: Static Analysis
                 run: vendor/bin/phpstan analyse

.github/workflows/Tests.yml

@@ -10,7 +10,7 @@ jobs:
         strategy:
             fail-fast: true
             matrix:
-                php-versions: ['7.1', '7.2', '7.3', '7.4']
+                php-versions: ['7.1', '7.2', '7.3', '7.4', '8.0']
 
         steps:
             -   name: Checkout
@@ -38,7 +38,7 @@ jobs:
         strategy:
             fail-fast: true
             matrix:
-                php-versions: ['7.1', '7.2', '7.3', '7.4']
+                php-versions: ['7.1', '7.2', '7.3', '7.4', '8.0']
 
         steps:
             -   name: Checkout

.gitignore

@@ -1,3 +1,4 @@
 /composer.lock
-/.php_cs.cache
+/.phpunit.result.cache
+/.php-cs-fixer.cache
 /vendor

.php-cs-fixer.dist.php

@@ -0,0 +1,24 @@
+<?php
+
+use PhpCsFixer\Config;
+use PhpCsFixer\Finder;
+
+$finder = Finder::create()
+    ->in(__DIR__ .'/examples')
+    ->in(__DIR__ .'/lib')
+    ->in(__DIR__ .'/test')
+    ->name('*.php')
+;
+
+$config = new Config();
+$config
+    ->setFinder($finder)
+    ->setRiskyAllowed(true)
+    ->setRules([
+        '@Symfony' => true,
+        '@Symfony:risky' => true,
+        'phpdoc_summary' => false,
+    ])
+;
+
+return $config;