re-license spec file to CECILL-2.1
raise dependency on PHP 7.4
raise dependency on phpdocumentor/type-resolver 1.7
add dependency on phpstan/phpdoc-parser
add dependency on doctrine/deprecations
raise dependency on phpdocumentor/type-resolver 1.3
raise dependency on webmozart/assert 1.9.1
raise dependency on phpdocumentor/reflection-common 2.2
raise build dependency on mockery/mockery 1.3.2
switch to phpunit9
