Merge pull request #8 from sweetrdf/feature/php8.5

PHP 8.5 support

.github/workflows/document.yml: bump checkout and cache actions version

Merge pull request #7 from sweetrdf/feature/reached-phpstan-level-4

Reached PHPStan (v2) level 6

Dataset: fix PHP 8.4 deprecations

.github/workflows/test.yml: run phpstan on PHP 8.4

DataFactory: avoid race conditions with PHP garbage collector

composer.json: bump rdf-interface to ^2

composer.json: bump rdfInterface to ^2.0.0-RC7

composer.json: allow both rdf-terms v1 and v2

Literal::__toString() returns a lexical form and NamedNode::__toStrin…

…g(): returs just the URI