New upstream version 2.1.0

.github/workflows/backward-compatibility.yml

.github/workflows/build.yml

.github/workflows/test-slevomat-coding-standard.yml

README.md

src/Ast/Attribute.php

src/Ast/Comment.php

src/Ast/NodeAttributes.php

src/Lexer/Lexer.php

src/Parser/PhpDocParser.php

src/Parser/TokenIterator.php

src/Parser/TypeParser.php

src/ParserConfig.php

src/Printer/Printer.php

tests/PHPStan/Parser/PhpDocParserTest.php

tests/PHPStan/Parser/TypeParserTest.php

tests/PHPStan/Printer/PrinterTest.php